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In the ], '''mathematics in medieval Islam''', often termed '''Islamic mathematics''' or '''Arabic mathematics''', is the ] developed in the ] between 622 and 1600, during what is known as the ], in that part of the world where ] was the dominant religion. ] and mathematics flourished under the Islamic ] (also known as the Islamic Empire) established across the Middle East, ], ], ], the ], and, at its peak, parts of France and ] as well. Islamic activity in mathematics was largely centered around modern-day ] and ], but at its greatest extent stretched from North Africa and Spain in the west to India in the east.<ref>O'Connor 1999</ref> | |||
]'' by ]]] | |||
] during the ], especially during the 9th and 10th centuries, was built upon syntheses of ] (], ], ]) and ] (], ]). Important developments of the period include extension of the ] to include ], the systematised study of ] and advances in ] and ].<ref>{{harvp|Katz|1993}}: "A complete history of mathematics of medieval Islam cannot yet be written, since so many of these Arabic manuscripts lie unstudied... Still, the general outline... is known. In particular, Islamic mathematicians fully developed the decimal place-value number system to include decimal fractions, systematised the study of algebra and began to consider the relationship between algebra and geometry, studied and made advances on the major Greek geometrical treatises of Euclid, Archimedes, and Apollonius, and made significant improvements in plane and spherical geometry."<br/> | |||
While most scientists in this period were ]s and wrote in ],<ref name=Hogendijk/> many of the best known contributors were ]<ref>Joseph A. Schumpeter, Historian of Economics: Selected Papers from the History of Economics Society Conference, 1994, y Laurence S. Moss, Joseph Alois Schumpeter, History of Economics Society. Conference, Published by Routledge, 1996, ISBN 041513353X, p. 64. Excerpt: ''A great portion (and most of the best) of medieval Muslim philosophers, physicians, ethicists, scientists, Islamic jurists, historians, and geographers were Persian-speaking Iranians''</ref><ref name=Franz>], Franz Rosenthal, N. J. Dawood (1967), ''The Muqaddimah: An Introduction to History'', p. X, ], ISBN 0691017549. p. 430: "Only the Persians engaged in the task of preserving knowledge and writing systematic scholarly works. Thus, the truth of the following statement by the Prophet becomes apparent:"If scholarship hung suspended in the highest parts of heaven, the Persians would attain it. This situation continued in the cities as long as the Persians and the Persian countries, the 'Iraq, Khurasan, and Transoxania, retained their sedentary culture. But when those cities fell into ruins, sedentary culture, which God has devised for the attainment of sciences and crafts, disappeared from them. Along with it, scholarship altogether disappeared from among the non-Arabs (Persians), who were (now) engulfed by the desert attitude. Scholarship was restricted to cities with an abundant sedentary culture. Today, no (city) has a more abundant sedentary culture than Cairo (Egypt). It is the mother of the world, the great center (Iwan) of Islam, and the mainspring of the sciences and the crafts. Some sedentary culture has also survived in Transoxania, because the dynasty there provides some sedentary culture. Therefore, they have there a certain number of the sciences and the crafts, which cannot be denied. Our attention was called to this fact by the contents of the writings of a (Transoxanian) scholar, which have reached us in this country. He is ]. As far as the other non-Arabs (Persians) are concerned, we have not seen, since the imam ] and ], any discussions that could be referred to as indicating their ultimate excellence."</ref> as well as ]s,<ref name=Franz/> in addition to ], ] and ] contributors, as well as some from other religions (]s, ]s, ], ], and the ]).<ref name=Hogendijk>Hogendijk 1999</ref> Arabic was the dominant language—much like ] in ], Arabic was the written '']'' of most scholars throughout the Islamic world. In this article, "Islam" and the adjective "Islamic" are used to describe the ] rather than the religion. | |||
^ {{harvp|Smith|1958|loc=Vol. 1, Chapter VII.4}}: "In a general way it may be said that the Golden Age of Arabian mathematics was confined largely to the 9th and 10th centuries; that the world owes a great debt to Arab scholars for preserving and transmitting to posterity the classics of Greek mathematics; and that their work was chiefly that of transmission, although they developed considerable originality in algebra and showed some genius in their work in trigonometry."</ref> | |||
The ] underwent significant developments in mathematics. ] played a key role in this transformation, introducing algebra as a distinct field in the 9th century. ]'s approach, departing from earlier arithmetical traditions, laid the groundwork for the arithmetization of ], influencing mathematical thought for an extended period. Successors like ] expanded on his work, contributing to advancements in various mathematical domains. The practicality and broad applicability of these mathematical methods facilitated the dissemination of Arabic mathematics to the West, contributing substantially to the evolution of Western mathematics.<ref>{{cite book |last1=Lumpkin |first1=Beatrice |url=https://archive.org/details/goldenageofmoor00vans |title=Golden age of the Moor, Volume 11 |last2=Zitler |first2=Siham |publisher=Transaction Publishers |year=1992 |isbn=1-56000-581-5 |editor-last=Van Sertima |editor-first=Ivan |editor-link=Ivan van Sertima |page= |chapter=Cairo: Science Academy of the Middle Ages}} "The Islamic mathematicians exercised a prolific influence on the development of science in Europe, enriched as much by their own discoveries as those they had inherited by the Greeks, the Indians, the Syrians, the Babylonians, etc."</ref> | |||
==Origins and influences== | |||
The first century of the ]ic ] saw almost no scientific or mathematical achievements, since the Arabs, with their newly conquered empire, had not yet gained any intellectual drive and research in other parts of the world had faded. In the second half of the 8th century Islam had a cultural awakening, and research in mathematics and the sciences increased.<ref name="Boyer Intro Islamic Algebra">{{Citation|last=Boyer|authorlink=Carl Benjamin Boyer|title=|year=1991|chapter=The Arabic Hegemony|quote=The first century of the Muslim empire had been devoid of scientific achievement. This period (from about 650 to 750) had been, in fact, perhaps the nadir in the development of mathematics, for the Arabs had not yet achieved intellectual drive, and concern for learning in other parts of the world had faded. Had it not been for the sudden cultural awakening in Islam during the second half of the eighth century, considerably more of ancient science and mathematics would have been lost. It was during the caliphate of al-Mamun (809–833), however, that the Arabs fully indulged their passion for translation. The caliph is said to have had a dream in which Aristotle appeared, and in the new world peolpe nee fjjdhew r | |||
as a consequence al-Mamun determined to have Arabic versions made of all the Greek works that he could lay his hands on, including Ptolemy's ''Almagest'' and a complete version of Euclid's ''Elements''. From the Byzantine Empire, with which the Arabs maintained an uneasy peace, Greek manuscripts were obtained through peace treaties. Al-Mamun established at Baghdad a "House of Wisdom" (Bait al-hikma) comparable to the ancient Museum at Alexandria. Among the faculty members was a mathematician and astronomer, Mohammed ibn-Musa al-Khwarizmi, whose name, like that of Euclid, later was to become a household word in Western Europe. The scholar, who died sometime before 850, wrote more than half a dozen astronomical and mathematical works, of which the earliest were probably based on the ''Sindhad'' derived from India.|page=227}}</ref> The Muslim ] ] ] (809–833) is said to have had a dream where Aristotle appeared to him, and as a consequence al-Mamun ordered that Arabic translation be made of as many Greek works as possible, including Ptolemy's '']'' and Euclid's '']''. Greek works would be given to the Muslims by the ] in exchange for treaties, as the two empires held an uneasy peace.<ref name="Boyer Intro Islamic Algebra" /> Many of these Greek works were translated by ] (826–901), who translated books written by ], ], Apollonius, ], and Eutocius.<ref name="Boyer Islamic Rhetoric Algebra Thabit">{{Citation|last=Boyer|authorlink=Carl Benjamin Boyer|title=|year=1991|chapter=The Arabic Hegemony|quote=but al-Khwarizmi's work had a serious deficiency that had to be removed before it could serve its purpose effectively in the modern world: a symbolic notation had to be developed to replace the rhetorical form. This step the Arabs never took, except for the replacement of number words by number signs. Thabit was the founder of a school of translators, especially from Greek and Syriac, and to him we owe an immense debt for translations into Arabic of works by Euclid, ], ], ], and ].|page=234}}</ref> Historians are in debt to many Islamic translators, for it is through their work that many ancient Greek texts have survived only through ] translations.{{Citation needed|date=November 2010}} | |||
Arabic mathematical knowledge spread through various channels during the ], driven by the practical applications of ]'s methods. This dissemination was influenced not only by economic and political factors but also by cultural exchanges, exemplified by events such as the ] and the translation movement. The ], spanning from the 8th to the 14th century, marked a period of considerable advancements in various scientific disciplines, attracting scholars from medieval Europe seeking access to this knowledge. Trade routes and cultural interactions played a crucial role in introducing Arabic mathematical ideas to the West. The translation of Arabic mathematical texts, along with Greek and Roman works, during the 14th to 17th century, played a pivotal role in shaping the intellectual landscape of the ]. | |||
], ] and ] all played an important role in the development of early Islamic mathematics. The works of mathematicians such as Euclid, ], Archimedes, ], ] and ] were all acquired by the Islamic world and incorporated into their mathematics. Perhaps the most influential mathematical contribution from India was the decimal ] ], also known as the ].<ref name="Berggren Islamic mathematics">{{Citation | |||
| first=J. Lennart | |||
| last=Berggren | |||
| title=The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A Sourcebook | |||
| chapter=Mathematics in Medieval Islam | |||
| publisher=Princeton University Press | |||
| year=2007 | |||
| isbn=9780691114859 | |||
| quote=The mathematics, to speak only of the subject of interest here, came principally from three traditions. The first was Greek mathematics, from the great geometrical classics of Euclid, Apollonius, and Archimedes, through the numerical solutions of indeterminate problems in Diophantus's ''Arithmatica'', to the practical manuals of Heron. But, as Bishop Severus Sebokht pointed out in the mid-seventh century, "there are also others who know something." Sebokht was referring to the Hindus, with their in genius arithmetic system based on only nine signs and a dot for an empty place. But they also contributed algebraic methods, a nascent trigonometry, and methods from solid geometry to solve problems in astronomy. The third tradition was what one may call the mathematics of practitioners. Their numbers included surveyors, builders, artisans, in geometric design, tax and treasury officials, and some merchants. Part of an oral tradition, this mathematics transcended ethnic divisions and was common heritage of many of the lands incorporated into the Islamic world. | |||
| page=516 | |||
}}</ref> The ] historian ] (c. 1050) in his book ''Tariq al-Hind'' states that ] had an embassy in India from which was brought a book to Baghdad that was translated into Arabic as ''Sindhind''. It is generally assumed that ''Sindhind'' is none other than Brahmagupta's '']''.<ref name="Boyer Siddhanta">{{Citation|last=Boyer|authorlink=Carl Benjamin Boyer|title=|year=1991|chapter=The Arabic Hegemony|quote=By 766 we learn that an astronomical-mathematical work, known to the Arabs as the ''Sindhind'', was brought to Baghdad from India. It is generally thought that this was the ''Brahmasphuta Siddhanta'', although it may have been the ''Surya Siddhanata''. A few years later, perhaps about 775, this ''Siddhanata'' was translated into Arabic, and it was not long afterwards (ca. 780) that Ptolemy's astrological ''Tetrabiblos'' was translated into Arabic from the Greek.|page=226}}</ref> The earliest translations from Sanskrit inspired several astronomical and astrological Arabic works, now mostly lost, some of which were even composed in verse.<ref name="Plofker 434"/> ] described the ], a treatise by the Indian Mathematician ], as a "mix of common pebbles and costly crystals".<ref>{{Harv|Boyer|1991|loc="China and India" p. 211}}</ref> | |||
== Origin and spread of Arab-Islamic mathematics == | |||
Indian influences were later overwhelmed by Greek mathematical and astronomical texts. It is not clear why this occurred but it may have been due to the greater availability of Greek texts in the region, the larger number of practitioners of Greek mathematics in the region, or because Islamic mathematicians favored the deductive exposition of the Greeks over the elliptic Sanskrit verse of the Indians. Regardless of the reason, Indian mathematics soon became mostly eclipsed by or merged with the "Graeco-Islamic" science founded on Hellenistic treatises.<ref name="Plofker 434">{{Citation | first = Kim | last = Plofker | year = 2007 | title = | quote = The early translations from Sanskrit inspired several other astronomical/astrological works in Arabic; some even imitated the Sanskrit practice of composing technical treatises in verse. Unfortunately, the earliest texts in this genre have now mostly been lost, and are known only from scattered fragments and allusions in later works. They reveal that the emergent Arabic astronomy adopted many Indian parameters, cosmological models, and computational techniques, including the use of sines.<BR>These Indian influences were soon overwhelmed – although it is not completely clear why – by those of the Greek mathematical and astronomical texts that were translated into Arabic under the Abbasid caliphs. Perhaps the greater availability of Greek works in the region, and of practitioners who understood them, favored the adoption of the Greek tradition. Perhaps its prosaic and deductive expositions seemed easier for foreign readers to grasp than elliptic Sanskrit verse. Whatever the reasons, Sanskrit inspired astronomy was soon mostly eclipsed by or merged with the "Graeco-Islamic" science founded on Hellenistic treatises. | page = 434}}</ref> Another likely reason for the declining Indian influence in later periods was due to ] achieving independence from the ], thus limiting access to Indian works. Nevertheless, Indian methods continued to play an important role in algebra, arithmetic and trigonometry.<ref>{{citation|first=Syed Nomanul|last=Haq|title=The Indian and Persian background|pages=60–3}}, in {{citation|title=History of Islamic Philosophy|first=Oliver Leaman|last=]|year=1996|publisher=]|isbn=0415131596|pages=52–70}}</ref> | |||
Arabic mathematics, particularly algebra, developed significantly during the ]. ]'s ({{Langx|ar|محمد بن موسى الخوارزمي}}; {{Circa|780|850}}) work between AD 813 and 833 in Baghdad was a turning point. He introduced the term "algebra" in the title of his book, "]," marking it as a distinct discipline. He regarded his work as "a short work on Calculation by (the rules of) Completion and Reduction, confining it to what is easiest and most useful in arithmetic".<ref name="ben Musa-2013">{{Cite book |last=ben Musa |first=Mohammed |url=http://dx.doi.org/10.1017/cbo9781139505871 |title=The Algebra of Mohammed ben Musa |date=2013-03-28 |publisher=Cambridge University Press |isbn=978-1-108-05507-9}}</ref> Later, people commented his work was not just a theoretical treatise but also practical, aimed at solving problems in areas like commerce and land measurement. | |||
]'s approach was groundbreaking in that it did not arise from any previous "arithmetical" tradition, including that of ]. He developed a new vocabulary for algebra, distinguishing between purely algebraic terms and those shared with arithmetic. Al-Khwārizmī noticed that the representation of numbers is crucial in daily life. Thus, he wanted to find or summarize a way to simplify the mathematical operation, so-called later, the algebra.<ref name="ben Musa-2013" /> His algebra was initially focused on linear and quadratic equations and the elementary arithmetic of binomials and trinomials. This approach, which involved solving equations using radicals and related algebraic calculations, influenced mathematical thinking long after his death. | |||
Besides the Greek and Indian tradition, a third tradition which had a significant influence on mathematics in medieval Islam was the "mathematics of practitioners", which included the applied mathematics of "surveyors, ], ], in geometric design, ]." This applied form of mathematics transcended ethnic divisions and was a common heritage of the lands incorporated into the Islamic world.<ref name="Berggren Islamic mathematics"/> This tradition also includes the religious observances specific to Islam, which served as a major impetus for the development of mathematics as well as astronomy.<ref name=Gingerich/> | |||
Al-Khwārizmī's proof of the rule for solving ] of the form (ax^2 + bx = c), commonly referred to as "squares plus roots equal numbers," was a monumental achievement in the history of algebra. This breakthrough laid the groundwork for the systematic approach to solving quadratic equations, which became a fundamental aspect of algebra as it developed in the Western world.<ref name="Swetz-2012">{{Cite report |url=http://dx.doi.org/10.4169/loci003901 |title=Mathematical Treasures: Mesopotamian Accounting Tokens |last=Swetz |first=Frank J. |date=2012-08-15 |publisher=The MAA Mathematical Sciences Digital Library |location=Washington, DC}}</ref> Al-Khwārizmī's method, which involved completing the square, not only provided a practical solution for equations of this type but also introduced an abstract and generalized approach to mathematical problems. His work, encapsulated in his seminal text "Al-Kitab al-Mukhtasar fi Hisab al-Jabr wal-Muqabala" (The Compendious Book on Calculation by Completion and Balancing), was translated into ] in the 12th century. This translation played a pivotal role in the transmission of algebraic knowledge to Europe, significantly influencing mathematicians during the Renaissance and shaping the evolution of modern mathematics.<ref name="Swetz-2012" /> Al-Khwārizmī's contributions, especially his proof for quadratic equations, are a testament to the rich mathematical heritage of the Islamic world and its enduring impact on Western mathematics. | |||
===Islam and mathematics=== | |||
A major impetus for the flowering of mathematics as well as ] came from religious observances, which presented an assortment of problems in astronomy and mathematics, specifically in ], ],<ref name=Gingerich>{{Citation |last=Gingerich |first=Owen |date = April 1986|url=http://faculty.kfupm.edu.sa/PHYS/alshukri/PHYS215/Islamic_astronomy.htm |title=Islamic astronomy |journal=] |volume=254 |issue=10 |page=74 |accessdate=2008-05-18 }}</ref> ]<ref name=Gandz/> and ].{{Citation needed|date=May 2010}} | |||
The spread of Arabic mathematics to the West was facilitated by several factors. The practicality and general applicability of al-Khwārizmī's methods were significant. They were designed to convert numerical or geometrical problems into equations in normal form, leading to canonical solution formulae. His work and that of his successors like ] laid the foundation for advances in various mathematical fields, including ], ], and ].<ref>{{Cite web |title=Extending al-Karaji's Work on Sums of Odd Powers of Integers - Introduction {{!}} Mathematical Association of America |url=https://maa.org/press/periodicals/convergence/extending-al-karajis-work-on-sums-of-odd-powers-of-integers-introduction |access-date=2023-12-15 |website=maa.org |language=en}}</ref> | |||
The ] served as an impetus behind the development of algebra (derived from the ] ''al-jabr'') by ] and other medieval Islamic mathematicians. Al-Khwārizmī's '']'' devoted a chapter on the solution to the Islamic law of inheritance using algebra. He formulated the rules of inheritance as ]s, hence his knowledge of ]s was not required.<ref name=Gandz>{{citation|title=The Algebra of Inheritance: A Rehabilitation of Al-Khuwarizmi|first=Solomon|last=Gandz|journal=]|volume=5|year=1938|publisher=]|pages=319–91|doi=10.1086/368492}}</ref> Later mathematicians who specialized in the Islamic law of inheritance included ], who developed the modern symbolic ] for ] in the 12th century,{{Citation needed|date=May 2010}} and ], who developed an algebraic notation which took "the first steps toward the introduction of algebraic symbolism" in the 15th century.<ref name=Qalasadi/> | |||
Al-Khwārizmī's algebra was an autonomous discipline with its historical perspective, eventually leading to the "arithmetization of algebra". His successors expanded on his work, adapting it to new theoretical and technical challenges and reorienting it towards a more arithmetical direction for abstract algebraic calculation. | |||
In order to observe holy days on the ] in which timings were determined by ], astronomers initially used ]'s method to calculate the place of the ] and ]s. The method Ptolemy used to solve ]s, however, was a clumsy one devised late in the 1st century by ]. It involved setting up two intersecting ]s; by applying ] it was possible to solve one of the six sides, but only if the other five sides were known. To tell the time from the ]'s ], for instance, repeated applications of Menelaus' theorem were required. For medieval Islamic astronomers, there was an obvious challenge to find a simpler ] method.<ref name=Gingerich/> | |||
Arabic mathematics, epitomized by al-Khwārizmī's work, was crucial in shaping the mathematical landscape. Its spread to the West was driven by its practical applications, the expansion of mathematical concepts by his successors, and the translation and adaptation of these ideas into the Western context. This spread was a complex process involving economics, politics, and cultural exchange, greatly influencing Western mathematics. | |||
Regarding the issue of moon sighting, Islamic months do not begin at the astronomical ], defined as the time when the moon has the same ] as the sun and is therefore invisible; instead they begin when the thin ] is first sighted in the western evening sky.<ref name=Gingerich/> The Qur'an says: "They ask you about the waxing and waning phases of the crescent moons, say they are to mark fixed times for mankind and ]."<ref>{{cite quran|2|189|style=ref}}</ref><ref>{{citation|url=http://www.almizan.org/Tafseer/Volume3/Baqarah47.asp|chapter=Volume 3: Surah Baqarah, Verse 189|author=Syed Mohammad Hussain Tabatabai|title=Tafsir al-Mizan|accessdate=2008-01-24}} {{Dead link|date=October 2010|bot=H3llBot}}</ref> This led Muslims to find the phases of the moon in the sky, and their efforts led to new mathematical calculations.<ref>{{cite web|url=http://www.chowk.com/site/articles/index.php?id=4026|title=The Science of Moon Sighting|author=Khalid Shaukat|date= September 23, 1997|accessdate=2008-01-24}}</ref> | |||
The period known as the ] (8th to 14th century) was characterized by significant advancements in various fields, including ]. Scholars in the Islamic world made substantial contributions to ], ], ], and other ]. As a result, the intellectual achievements of Islamic scholars attracted the attention of scholars in medieval Europe who sought to access this wealth of knowledge. Trade routes, such as the ], facilitated the movement of goods, ideas, and knowledge between the East and West. Cities like ], ], and ] became centers of learning and attracted scholars from different cultural backgrounds. Therefore, mathematical knowledge from the Islamic world found its way to Europe through various channels. Meanwhile, the ] connected Western Europeans with the Islamic world. While the primary purpose of the Crusades was military, there was also cultural exchange and exposure to Islamic knowledge, including mathematics. European scholars who traveled to the Holy Land and other parts of the Islamic world gained access to Arabic manuscripts and mathematical treatises. During the 14th to 17th century, the translation of Arabic mathematical texts, along with ] and ] ones, played a crucial role in shaping the intellectual landscape of the Renaissance. Figures like ], who studied in North Africa and the Middle East, helped introduce and popularize Arabic numerals and mathematical concepts in Europe. | |||
Predicting just when the crescent moon would become visible is a special challenge to Islamic mathematical astronomers. Although Ptolemy's theory of the complex lunar motion was tolerably accurate near the time of the new moon, it specified the moon's path only with respect to the ]. To predict the first visibility of the moon, it was necessary to describe its motion with respect to the ], and this problem demands fairly sophisticated spherical geometry. Finding the direction of ] and the time of ] are the reasons which led to Muslims developing spherical geometry. Solving any of these problems involves finding the unknown sides or angles of a triangle on the ] from the known sides and angles. A way of finding the time of day, for example, is to construct a triangle whose ] are the ], the north ], and the sun's position. The observer must know the altitude of the sun and that of the pole; the former can be observed, and the latter is equal to the observer's ]. The time is then given by the angle at the intersection of the ] (the ] through the zenith and the pole) and the sun's hour circle (the arc through the sun and the pole).<ref name=Gingerich/><ref name=Tabatabai/> | |||
== Concepts == | |||
Muslims are also expected to pray towards the ] in ] and orient their ]s in that direction. Thus they need to determine the direction of Mecca (]) from a given location.<ref>{{cite quran|2|144|style=ref}}</ref><ref>{{cite quran|2|150|style=ref}}</ref> Another problem is the time of ]. Muslims need to determine from ] the proper times for the prayers before ], at ], in the ], at ], and in the ].<ref name=Gingerich/><ref name=Tabatabai>{{citation|url=http://www.almizan.org/Tafseer/Volume2/Baqarah32.asp|author=Syed Mohammad Hussain Tabatabai|work=Tafsir al-Mizan|chapter=Volume 2: Surah Baqarah, Verses 142–151|accessdate=2008-01-24}} {{Dead link|date=October 2010|bot=H3llBot}}</ref> | |||
]'s "Cubic equations and intersections of conic sections" the first page of the two-chaptered manuscript kept in Tehran University]] | |||
== |
=== Algebra === | ||
{{further|History of algebra}} | |||
J. J. O'Conner and E. F. Robertson wrote in the '']'': | |||
{{quote|"Recent research paints a new picture of the debt that we owe to Islamic mathematics. Certainly many of the ideas which were previously thought to have been brilliant new conceptions due to European mathematicians of the 16th, 17th, and 18th centuries are now known to have been developed by Arabic/Islamic mathematicians around four centuries earlier. In many respects, the mathematics studied today is far closer in style to that of Islamic mathematics than to that of ]."}} | |||
The study of ], the name of which is derived from the ] word meaning completion or "reunion of broken parts",<ref>{{cite web |title=algebra |work=] |url=http://www.etymonline.com/index.php?term=algebra&allowed_in_frame=0}}</ref> flourished during the ]. ], a Persian scholar in the ] in ] was the founder of algebra, is along with the ] mathematician ], known as the father of algebra. In his book '']'', Al-Khwarizmi deals with ways to solve for the ] ]s of first and second-degree (linear and quadratic) ]. He introduces the method of ], and unlike Diophantus, also gives general solutions for the equations he deals with.{{sfn|Boyer|1991|p=}}<ref>{{cite book|last=Swetz |first=Frank J. |title=Learning Activities from the History of Mathematics |url=https://books.google.com/books?id=zVYMoKhU_roC&pg=PA26 |year=1993|publisher=Walch Publishing |isbn=978-0-8251-2264-4 |page=26}}</ref><ref name=Gullberg>{{cite book |last1=Gullberg |first1=Jan |author-link=Jan Gullberg |title=Mathematics: From the Birth of Numbers |url=https://archive.org/details/mathematicsfromb1997gull |url-access=registration |date=1997 |publisher=W. W. Norton |isbn=0-393-04002-X |page=}}</ref> | |||
R. Rashed wrote in ''The development of Arabic mathematics: between arithmetic and algebra'': | |||
{{quote|"]'s successors undertook a systematic application of ] to ], algebra to arithmetic, both to ], algebra to the ]ean ], algebra to ], and geometry to algebra. This was how the creation of ], ], ], the numerical solution of ]s, the new elementary theory of numbers, and the geometric construction of equations arose."}} | |||
Al-Khwarizmi's algebra was rhetorical, which means that the equations were written out in full sentences. This was unlike the algebraic work of Diophantus, which was syncopated, meaning that some symbolism is used. The transition to symbolic algebra, where only symbols are used, can be seen in the work of ] and ].<ref>{{MacTutor|id=Al-Banna|title=al-Marrakushi ibn Al-Banna}}</ref><ref name=Gullberg/> | |||
== Biographies == | |||
;{{transl|ar|ALA|]}} (786–833) | |||
:Al-Ḥajjāj translated ]'s '']'' into Arabic. | |||
;{{transl|ar|ALA|]}} (c. 780 ]/] – c. 850 Baghdad) <!-- JPH MT AMFB --> | |||
:Al-Khwārizmī was a Persian ], ], ] and ]. He worked most of his life as a ] in the ] in ]. His '']'' was the first book on the systematic solution of ] and ]s. ] translations of his ''Arithmetic'', on the ], introduced the ] ] to the ] in the 12th century. He revised and updated ]'s ''Geography'' as well as writing several works on astronomy and astrology. | |||
;{{transl|ar|ALA|]}} (c. 800 Baghdad? – c. 860 Baghdad?)<!-- MT --> | |||
:Al-Jawharī was a mathematician who worked at the House of Wisdom in Baghdad. His most important work was his ''Commentary on ]'' which contained nearly 50 additional ]s and an attempted ] of the ]. | |||
;{{transl|ar|ALA|]}} (] 830 Baghdad) <!-- JPH --> | |||
:Ibn Turk wrote a work on ] of which only a chapter on the solution of ] has survived. | |||
;{{transl|ar|ALA|]}} (c. 801 ] – 873 Baghdad) <!-- JPH MT AMFB --> | |||
:Al-Kindī (or Alkindus) was a ] and ] who worked as the House of Wisdom in Baghdad where he wrote commentaries on many Greek works. His contributions to mathematics include many works on ] and ]. | |||
;] (808 ] – 873 Baghdad) <!-- MT --> | |||
: Hunayn (or Johannitus) was a translator who worked at the House of Wisdom in Baghdad. Translated many Greek works including those by ], ], ], ], and the ]. | |||
;{{transl|ar|ALA|]}} (c. 800 Baghdad – 873+ Baghdad) <!-- JPH AMFB --> | |||
:The Banū Mūsā were three brothers who worked at the House of Wisdom in Baghdad. Their most famous mathematical treatise is ''The Book of the Measurement of Plane and Spherical Figures'', which considered similar problems as ] did in his '']'' and ''On the sphere and the cylinder''. They contributed individually as well. The eldest, {{transl|ar|ALA|]}} (c. 800) specialised in geometry and astronomy. He wrote a critical revision on ]' ''Conics'' called ''Premises of the book of conics''. {{transl|ar|ALA|]}} (c. 805) specialised in mechanics and wrote a work on ] devices called ''On mechanics''. The youngest, {{transl|ar|ALA|]}} (c. 810) specialised in geometry and wrote a work on the ] called ''The elongated circular figure''. | |||
;] <!-- MT --> | |||
;] <!-- MT --> | |||
;] (Syria-Iraq, 835–901) <!-- JPH MT --> | |||
;] (Iraq? ca. 850–900) <!-- JPH --> | |||
;{{transl|ar|ALA|]}} (c. 853 ] – 929 ] near ]) <!-- JPH (Syria, ca. 900) MT --> | |||
;] (Egypt? ca. 900) <!-- JPH MT --> | |||
;] (ca. 880 – 943) <!-- MT --> | |||
;] <!-- MT --> | |||
;] (Iraq, 909–946) <!-- JPH MT --> | |||
;] (Iraq-Iran, ca. 920–980) <!-- JPH MT --> | |||
;] (Iraq? 10th century?) <!-- JPH --> | |||
;] (Iraq, first half of 10th century) <!-- JPH --> | |||
:The Ikhwan al-Safa' ("brethren of purity") were a (mystical?) group in the city of Basra in Irak. The group authored a series of more than 50 letters on science, philosophy and theology. The first letter is on arithmetic and number theory, the second letter on geometry. | |||
;] (Iraq-Iran, 10th century) <!-- JPH MT --> | |||
;] (Iraq-Iran, ca. 940–1000) <!-- JPH --> | |||
;{{transl|ar|ALA|]}} (Iraq-Iran, ca. 940–1000) <!-- JPH MT --> | |||
;] <!-- MT --> | |||
;{{transl|ar|ALA|]}} (Iraq-Iran, ca. 940–998) <!-- JPH MT --> | |||
;] (Iraq-Iran, ca. 940–1000) <!-- JPH --> | |||
;] (Iran, ca. 940–1000) <!-- JPH MT --> | |||
;] (], ca. 10th century) | |||
:One of the few Islamic female mathematicians known by name, and the secretary of the ] al-Hakem II. She was well-versed in the exact sciences, and could solve the most complex geometrical and algebraic problems known in her time.<ref>{{Citation|author=|title=History of the Moorish Empire in Europe|publisher=J.B. Lippincott Company|location=Philadelphia & London|year=1904|edition=1|volume=3|page=447|chapter=xxix: Moorish art in southern Europe|isbn=978-1402144851 (published in 2004)|oclc=3522061|url=http://www.archive.org/stream/historyofmoorish03scotuoft#page/447/mode/1up|accessdate=2010-01-15}}</ref> | |||
;] (Egypt, ca. 950–1010) <!-- JPH MT --> | |||
;] (Iraq-Iran, ca. 950–1030) <!-- JPH MT --> | |||
;] (Iran, ca. 960–1010) <!-- JPH --> | |||
;] (Iran, ca. 970–1030) <!-- JPH MT --> | |||
;] (Iraq-Egypt, ca. 965–1040) <!-- JPH MT --> | |||
;{{transl|ar|ALA|]}} (September 15, 973 in Kath, ] – December 13, 1048 in ]) <!-- JPH MT --> | |||
;] (also known as Avicenna) (])<!-- MT --> | |||
;] <!-- MT --> | |||
;] <!-- MT --> | |||
;] (], ca. 1030–1090) <!-- JPH MT --> | |||
;] (Azarquiel, al-Zarqali) (], ca. 1030–1090) <!-- JPH --> | |||
;] (], ca. 1080) <!-- JPH --> | |||
;] (Iran, ca. 1050–1130) <!-- JPH MT --> | |||
;{{transl|ar|ALA|]}} (ca. 1130, ] – c. 1180, ]) <!-- MT --> | |||
;] (ca. 12th century, ]) | |||
:Developed the modern ] for ] and the digits he uses for the ''ghubar'' numerals also closely resembles modern Western ]. | |||
;] (ca. 12th century, ]) | |||
:The son of a ] father and ] mother, he was the first to develop a mathematical notation for algebra since the time of ]. | |||
;{{transl|ar|ALA|]}} (Iran, ca. 1150–1215) <!-- JPH MT --> | |||
;] (], ca. 1210) <!-- JPH --> | |||
;] (], 1250–1320) <!-- JPH --> | |||
;{{transl|ar|ALA|]}} (18 February 1201 in ], ] – 26 June 1274 in ] near ]) <!-- JPH MT --> | |||
;{{transl|ar|ALA|]}} (c. 1220 Spain – c. 1283 ]) <!-- MT --> | |||
;{{transl|ar|ALA|]}} (c. 1250 ] – c. 1310) <!-- MT --> | |||
;] (], ca. 1250–1320) <!-- JPH --> | |||
;] (Iran, ca. 1300) <!-- JPH MT --> | |||
;] (Syria, ca. 1350–1400) <!-- JPH MT --> | |||
;] (1306–1375) <!-- JPH --> | |||
;'''{{transl|ar|ALA|]}}''' (1364 ] – 1436 Samarkand) <!-- MT --> | |||
;{{transl|ar|ALA|]}} (Iran, Uzbekistan, ca. 1420) <!-- JPH MT --> | |||
;] (Iran, Uzbekistan, 1394–1449) <!-- JPH MT --> | |||
;] (])<!-- MT --> | |||
;] (], 1412–1482) <!-- JPH MT --> | |||
:Last major medieval ] mathematician. Pioneer of ]. | |||
On the work done by Al-Khwarizmi, J. J. O'Connor and ] said:<ref>{{MacTutor |class=HistTopics |id=Arabic_mathematics |title=Arabic mathematics: forgotten brilliance?}}</ref> | |||
==Algebra== | |||
]'' by ].]] | |||
{{quote|"Perhaps one of the most significant advances made by Arabic mathematics began at this time with the work of al-Khwarizmi, namely the beginnings of algebra. It is important to understand just how significant this new idea was. It was a revolutionary move away from the Greek concept of mathematics which was essentially geometry. Algebra was a unifying theory which allowed ], ]s, geometrical magnitudes, etc., to all be treated as "algebraic objects". It gave mathematics a whole new development path so much broader in concept to that which had existed before, and provided a vehicle for the future development of the subject. Another important aspect of the introduction of algebraic ideas was that it allowed mathematics to be applied to itself in a way which had not happened before." | ]}} | |||
The term ] is derived from the Arabic term ''al-jabr'' in the title of ]'s '']''. He originally used the term ''al-jabr'' to describe the method of "]" and "balancing", referring to the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation.<ref name=Boyer-229/> | |||
Several other mathematicians during this time period expanded on the algebra of Al-Khwarizmi. ] wrote a book of algebra accompanied with geometrical illustrations and proofs. He also enumerated all the possible solutions to some of his problems. ], ], along with ], found several solutions of the ]. Omar Khayyam found the general geometric solution of a cubic equation.{{Citation needed|date=April 2023|reason=Wasn't Scipione del Ferro the first one?}} | |||
There are three theories about the origins of Islamic algebra. The first emphasizes Hindu influence, the second emphasizes Mesopotamian or Persian-Syriac influence, and the third emphasizes Greek influence. Many scholars believe that it is the result of a combination of all three sources.<ref name="Boyer Three Influences on al Jabr">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977|page=230}} | |||
{{quote|"Al-Khwarizmi continued: "We have said enough so far as numbers are concerned, about the six types of equations. Now, however, it is necessary that we should demonstrate geometrically the truth of the same problems which we have explained in numbers." The ring of this passage is obviously Greek rather than Babylonian or Indian. There are, therefore, three main schools of thought on the origin of Arabic algebra: one emphasizes Hindu influence, another stresses the Mesopotamian, or Syriac-Persian, tradition, and the third points to Greek inspiration. The truth is probably approached if we combine the three theories."}}</ref> | |||
=== Cubic equations === | |||
Throughout their time in power, before the fall of Islamic civilization, the Arabs used a fully rhetorical algebra, where sometimes even the numbers were spelled out in words. The Arabs would eventually replace spelled out numbers (e.g. twenty-two) with ] (e.g. 22), but the Arabs never adopted or developed a syncopated or symbolic algebra,<ref name="Boyer Islamic Rhetoric Algebra Thabit">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977|page=234}} | |||
] ''x''<sup>2</sup> = ''ay'', a ] with diameter ''b''/''a''<sup>2</sup>, and a vertical line through the intersection point. The solution is given by the length of the horizontal line segment from the origin to the intersection of the vertical line and the ''x''-axis.]] | |||
{{quote|"but al-Khwarizmi's work had a serious deficiency that had to be removed before it could serve its purpose effectively in the modern world: a symbolic notation had to be developed to replace the rhetorical form. This step the Arabs never took, except for the replacement of number words by number signs. Thabit was the founder of a school of translators, especially from Greek and Syriac, and to him we owe an immense debt for translations into Arabic of works by Euclid, Archimedes, Apollonius, Ptolemy, and Eutocius."}}</ref> until the work of ] in the 13th century and ] in the 15th century.<ref name=Qalasadi/> | |||
{{further|Cubic equation}} | |||
] (c. 1038/48 in ] – 1123/24){{sfn|Struik|1987|p=96}} wrote the ''Treatise on Demonstration of Problems of Algebra'' containing the systematic solution of ], going beyond the ''Algebra'' of al-Khwārizmī.{{sfn|Boyer|1991|pp=241–242}} Khayyám obtained the solutions of these equations by finding the intersection points of two ]s. This method had been used by the Greeks,{{sfn|Struik|1987|p=97}} but they did not generalize the method to cover all equations with positive ].{{sfn|Boyer|1991|pp=241–242}} | |||
There were four conceptual stages in the development of algebra, three of which either began in, or were significantly advanced in, the Islamic world. These four stages were as follows:<ref>{{Citation|last=Victor J. Katz|first=Bill Barton|title=Stages in the History of Algebra with Implications for Teaching|journal=Educational Studies in Mathematics|publisher=]|volume=66|issue=2|date=October 2007|doi=10.1007/s10649-006-9023-7|pages=185–201|last2=Barton|first2=Bill}}</ref> | |||
<!--needs more context | |||
Khayyám differentiated between "geometric" and "arithmetic" solutions.{{sfn|Struik|1987|p=97}} Khayyám mistakenly believed{{sfn|Boyer|1991|pp=241–242}} arithmetic solutions only existed if the ] were ] and ].{{sfn|Struik|1987|p=97}} Khayyám did not concern himself with numerical calculations of the solutions.{{sfn|Struik|1987|p=97}} | |||
{{#tag:ref|"Omar Khayyam (ca. 1050–1123), the "tent-maker," wrote an ''Algebra'' that went beyond that of al-Khwarizmi to include equations of third degree. Like his predecessors, Omar Khayyam provided for quadratic equations both arithmetic and geometric solutions; for general cubic equations, he believed (mistakenly, as the sixteenth century later showed), arithmetic solutions were impossible; hence he gave only geometric solutions. The scheme of using intersecting conics to solve cubics had been used earlier by Menaechmus, Archimedes, and Alhazan, but Omar Khayyam took the praiseworthy step of generalizing the method to cover all third-degree equations (having positive roots). For equations of higher degree than three, Omar Khayyam evidently did not envision similar geometric methods, for space does not contain more than three dimensions, "{{sfn|Boyer|1991|pp=241–242}}|group="note"}} | |||
--> | |||
] (? in ] – 1213/4) developed a novel approach to the investigation of cubic equations—an approach which entailed finding the point at which a cubic polynomial obtains its maximum value. For example, to solve the equation <math>\ x^3 + a = b x</math>, with ''a'' and ''b'' positive, he would note that the maximum point of the curve <math>\ y = b x - x^3</math> occurs at <math>x = \textstyle\sqrt{\frac{b}{3}}</math>, and that the equation would have no solutions, one solution or two solutions, depending on whether the height of the curve at that point was less than, equal to, or greater than ''a''. His surviving works give no indication of how he discovered his formulae for the maxima of these curves. Various conjectures have been proposed to account for his discovery of them.<ref>{{cite journal |last1=Berggren |first1=J. Lennart |title=Innovation and Tradition in Sharaf al-Dīn al-Ṭūsī's ''al-Muʿādalāt'' |jstor=604533 |journal=Journal of the American Oriental Society |volume=110 |issue=2 |year=1990 |pages=304–309 |doi=10.2307/604533 |last2=Al-Tūsī |first2=Sharaf Al-Dīn |last3=Rashed |first3=Roshdi}}</ref> | |||
*'''Geometric stage''', where the concepts of algebra are largely ]. This dates back to the ] and continued with the ], and was revived by ]. | |||
{{Islamic studies sidebar}} | |||
*'''Static equation-solving stage''', where the objective is to find numbers satisfying certain relationships. The move away from geometric algebra dates back to ] and ], but algebra didn't decisively move to the static equation-solving stage until ]'s '']''. | |||
*'''Dynamic function stage''', where motion is an underlying idea. The idea of a ] began emerging with ], but algebra didn't decisively move to the dynamic function stage until ]. | |||
*'''Abstract stage''', where mathematical structure plays a central role. ] is largely a product of the 19th and 20th centuries. | |||
=== |
=== Induction === | ||
{{See also|Mathematical induction#History}} | |||
;Al-Khwarizmi and ''Al-jabr wa'l muqabalah'' | |||
The earliest implicit traces of mathematical induction can be found in ]'s ] (c. 300 BCE). The first explicit formulation of the principle of induction was given by ] in his {{Lang|fr|Traité du triangle arithmétique}} (1665). | |||
The Muslim<ref>{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|pages=228–229|isbn=0471543977}} | |||
{{quote|"the author's preface in Arabic gave fulsome praise to Mohammed, the prophet, and to al-Mamun, "the Commander of the Faithful"."}}</ref> | |||
Persian mathematician {{Unicode|]}} (c. 780–850) was a faculty member of the "House of Wisdom" (Bait al-hikma) in Baghdad, which was established by Al-Mamun. Al-Khwarizmi, who died around 850 AD, wrote more than half a dozen mathematical and astronomical works; some of which were based on the Indian ''Sindhind''.<ref name="Boyer Intro Islamic Algebra">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977|page=227}} | |||
{{quote|"The first century of the Muslim empire had been devoid of scientific achievement. This period (from about 650 to 750) had been, in fact, perhaps the nadir in the development of mathematics, for the Arabs had not yet achieved intellectual drive, and concern for learning in other parts of the world had faded. Had it not been for the sudden cultural awakening in Islam during the second half of the eighth century, considerably more of ancient science and mathematics would have been lost. It was during the caliphate of al-Mamun (809–833), however, that the Arabs fully indulged their passion for translation. The caliph is said to have had a dream in which Aristotle appeared, and as a consequence al-Mamun determined to have Arabic versions made of all the Greek works that he could lay his hands on, including Ptolemy's ''Almagest'' and a complete version of Euclid's ''Elements''. From the Byzantine Empire, with which the Arabs maintained an uneasy peace, Greek manuscripts were obtained through peace treaties. Al-Mamun established at Baghdad a "House of Wisdom" (Bait al-hikma) comparable to the ancient Museum at Alexandria. Among the faculty members was a mathematician and astronomer, Mohammed ibn-Musa al-Khwarizmi, whose name, like that of Euclid, later was to become a household word in Western Europe. The scholar, who died sometime before 850, wrote more than half a dozen astronomical and mathematical works, of which the earliest were probably based on the ''Sindhad'' derived from India."}}</ref> | |||
One of al-Khwarizmi's most famous books is entitled ''Al-jabr wa'l muqabalah'' or '']'', and it gives an exhaustive account of solving polynomials up to the second degree.<ref>{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977|page=228}} | |||
{{quote|"The Arabs in general loved a good clear argument from premise to conclusion, as well as systematic organization – respects in which neither Diophantus nor the Hindus excelled."}}</ref> The book also introduced the fundamental method of "]" and "balancing", referring to the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation. This is the operation which Al-Khwarizmi originally described as ''al-jabr''.<ref name=Boyer-229>{{Harv|Boyer|1991|loc="The Arabic Hegemony" p. 229}} "It is not certain just what the terms ''al-jabr'' and ''muqabalah'' mean, but the usual interpretation is similar to that implied in the translation above. The word ''al-jabr'' presumably meant something like "restoration" or "completion" and seems to refer to the transposition of subtracted terms to the other side of an equation; the word ''muqabalah'' is said to refer to "reduction" or "balancing" – that is, the cancellation of like terms on opposite sides of the equation."</ref> | |||
In between, implicit ] by induction for ] was introduced by ] (c. 1000) and continued by ], who used it for special cases of the ] and properties of ]. | |||
''Al-Jabr'' is divided into six chapters, each of which deals with a different type of formula. The first chapter of ''Al-Jabr'' deals with equations whose squares equal its roots (ax² = bx), the second chapter deals with squares equal to number (ax² = c), the third chapter deals with roots equal to a number (bx = c), the fourth chapter deals with squares and roots equal a number (ax² + bx = c), the fifth chapter deals with squares and number equal roots (ax² + c = bx), and the sixth and final chapter deals with roots and number equal to squares (bx + c = ax²).<ref name="Al Jabr and its chapters">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977 | |||
|quote=in six short chapters, of the six types of equations made up from the three kinds of quantities: roots, squares, and numbers (that is x, x<sup>2</sup>, and numbers). Chapter I, in three short paragraphs, covers the case of squares equal to roots, expressed in modern notation as x<sup>2</sup> = 5x, x<sup>2</sup>/3 = 4x, and 5x<sup>2</sup> = 10x, giving the answers x = 5, x = 12, and x = 2 respectively. (The root x = 0 was not recognized.) Chapter II covers the case of squares equal to numbers, and Chapter III solves the cases of roots equal to numbers, again with three illustrations per chapter to cover the cases in which the coefficient of the variable term is equal to, more than, or less than one. Chapters IV, V, and VI are mor interesting, for they cover in turn the three classical cases of three-term quadratic equations: (1) squares and roots equal to numbers, (2) squares and numbers equal to roots, and (3) roots and numbers equal to squares.|page=229}}</ref> | |||
=== Irrational numbers === | |||
J. J. O'Conner and E. F. Robertson wrote in the '']'': | |||
The Greeks had discovered ]s, but were not happy with them and only able to cope by drawing a distinction between ''magnitude'' and ''number''. In the Greek view, magnitudes varied continuously and could be used for entities such as line segments, whereas numbers were discrete. Hence, irrationals could only be handled geometrically; and indeed Greek mathematics was mainly geometrical. Islamic mathematicians including ] and ] slowly removed the distinction between magnitude and number, allowing irrational quantities to appear as coefficients in equations and to be solutions of algebraic equations.<ref name=Sesiano/><ref>{{MacTutor|id=Al-Baghdadi|title=Abu Mansur ibn Tahir Al-Baghdadi}}</ref> They worked freely with irrationals as mathematical objects, but they did not examine closely their nature.<ref>{{cite web |last1=Allen |first1=G. Donald |date=n.d. |title=The History of Infinity |publisher=Texas A&M University |url=http://www.math.tamu.edu/~dallen/history/infinity.pdf |access-date=7 September 2016}}</ref> | |||
In the twelfth century, ] translations of ]'s ] on the ] introduced the ] ] to the ].<ref name="Struik 93">{{harvnb|Struik|1987| p= 93}}</ref> His ''Compendious Book on Calculation by Completion and Balancing'' presented the first systematic solution of ] and ]s. In ] Europe, he was considered the original inventor of algebra, although it is now known that his work is based on older Indian or Greek sources.{{sfn|Rosen|1831|p=v–vi}}<ref>{{cite encyclopedia |last=Toomer |first=Gerald |author-link=Gerald Toomer |title=Al-Khwārizmī, Abu Ja'far Muḥammad ibn Mūsā |encyclopedia=] |volume=7 |editor=Gillispie, Charles Coulston |publisher=Charles Scribner's Sons |location=New York |date=1990 |isbn=0-684-16962-2 |url=http://www.encyclopedia.com/doc/1G2-2830902300.html |via=Encyclopedia.com}}</ref> He revised ]'s '']'' and wrote on astronomy and astrology. However, ] suggests that al-Khwarizmi's original work was not based on Ptolemy but on a derivative world map,{{sfn|Nallino|1939}} presumably in ] or ]. | |||
=== Spherical trigonometry === | |||
{{quote|"Perhaps one of the most significant advances made by Arabic mathematics began at this time with the work of al-Khwarizmi, namely the beginnings of algebra. It is important to understand just how significant this new idea was. It was a revolutionary move away from the Greek concept of mathematics which was essentially geometry. Algebra was a unifying theory which allowed ], ]s, geometrical magnitudes, etc., to all be treated as "algebraic objects". It gave mathematics a whole new development path so much broader in concept to that which had existed before, and provided a vehicle for future development of the subject. Another important aspect of the introduction of algebraic ideas was that it allowed mathematics to be applied to itself in a way which had not happened before."}} | |||
{{further|Law of sines|History of trigonometry}} | |||
The spherical ] was discovered in the 10th century: it has been attributed variously to ], ] and ], with ] as a contributor.<ref name=Sesiano>{{cite book | |||
The ] mathematician ] was traditionally known as "the father of algebra"<ref name="Carl Boyer For Al Khwarizmi">{{Harv|Boyer|1991|loc="The Arabic Hegemony" p. 228}} "Diophantus sometimes is called "the father of algebra," but this title more appropriately belongs to al-Khwarizmi. It is true that in two respects the work of al-Khwarizmi represented a retrogression from that of Diophantus. First, it is on a far more elementary level than that found in the Diophantine problems and, second, the algebra of al-Khwarizmi is thoroughly rhetorical, with none of the syncopation found in the Greek ''Arithmetica'' or in Brahmagupta's work. Even numbers were written out in words rather than symbols! It is quite unlikely that al-Khwarizmi knew of the work of Diophantus, but he must have been familiar with at least the astronomical and computational portions of Brahmagupta; yet neither al-Khwarizmi nor other Arabic scholars made use of syncopation or of negative numbers."</ref><ref name="John Derbyshire For Diophantus">{{Harv|Derbyshire|2006|loc="The Father of Algebra" p. 31}} "Diophantus, the father of algebra, in whose honor I have named this chapter, lived in Alexandria, in Roman Egypt, in either the 1st, the 2nd, or the 3rd century CE."</ref> but debate now exists as to whether or not ] deserves this title instead.<ref name="Carl Boyer For Al Khwarizmi"/> Those who support Diophantus point to the fact that the algebra found in ''Al-Jabr'' is more elementary than the algebra found in '']'' and that ''Arithmetica'' is syncopated while ''Al-Jabr'' is fully rhetorical.<ref name="Carl Boyer For Al Khwarizmi" /> Those who support Al-Khwarizmi point to the fact that he gave an exhaustive explanation for the algebraic solution of quadratic equations with positive roots,<ref>{{Harv|Boyer|1991|loc="The Arabic Hegemony" p. 230}} "The six cases of equations given above exhaust all possibilities for linear and quadratic equations having positive root. So systematic and exhaustive was al-Khwarizmi's exposition that his readers must have had little difficulty in mastering the solutions."</ref> introduced the fundamental methods of reduction and balancing,<ref name=Boyer-229/> and was the first to teach algebra in an ] and for its own sake, whereas Diophantus was primarily concerned with the ].<ref>Gandz and Saloman (1936), ''The sources of al-Khwarizmi's algebra'', Osiris i, pp. 263–277: "In a sense, Khwarizmi is more entitled to be called "the father of algebra" than Diophantus because Khwarizmi is the first to teach algebra in an elementary form and for its own sake, Diophantus is primarily concerned with the theory of numbers".</ref> In addition, R. Rashed and Angela Armstrong write: | |||
| last = Sesiano | first = Jacques | |||
| editor-last = Selin | editor-first = Helaine | editor-link = Helaine Selin | |||
| contribution = Islamic Mathematics | |||
| doi = 10.1007/978-94-011-4301-1_9 | |||
| isbn = 978-94-011-4301-1 | |||
| pages = 137–165 | |||
| publisher = Springer Netherlands | |||
| title = Mathematics Across Cultures: The History of Non-Western Mathematics | |||
| year = 2000}}</ref> ]'s ''The book of unknown arcs of a sphere'' in the 11th century introduced the general law of sines.<ref name="MacTutor Al-Jayyani">{{MacTutor |id=Al-Jayyani |title=Abu Abd Allah Muhammad ibn Muadh Al-Jayyani}}</ref> The plane law of sines was described in the 13th century by ]. In his ''On the Sector Figure'', he stated the law of sines for plane and spherical triangles and provided proofs for this law.{{sfn|Berggren|2007|p=518}} | |||
=== Negative numbers === | |||
{{quote|"Al-Khwarizmi's text can be seen to be distinct not only from the ], but also from Diophantus' ''Arithmetica''. It no longer concerns a series of ]s to be resolved, but an ] which starts with primitive terms in which the combinations must give all possible prototypes for equations, which henceforward explicitly constitute the true object of study. On the other hand, the idea of an equation for its own sake appears from the beginning and, one could say, in a generic manner, insofar as it does not simply emerge in the course of solving a problem, but is specifically called on to define an infinite class of problems."<ref>{{Citation | last1=Rashed | first1=R. | last2=Armstrong | first2=Angela | year=1994 | title=The Development of Arabic Mathematics | publisher=] | isbn=0792325656 | oclc=29181926 | pages=11–2}}</ref>}} | |||
{{further|Negative numbers}} | |||
In the 9th century, Islamic mathematicians were familiar with negative numbers from the works of Indian mathematicians, but the recognition and use of negative numbers during this period remained timid.<ref name=Rashed>{{Cite book| publisher = Springer| isbn = 9780792325659| last = Rashed| first = R.| title = The Development of Arabic Mathematics: Between Arithmetic and Algebra| date =1994-06-30|pages=36–37}}</ref> ] did not use negative numbers or negative coefficients.<ref name=Rashed /> But within fifty years, ] illustrated the rules of signs for expanding the multiplication <math>(a \pm b)(c \pm d)</math>.<ref name=Ismail>{{citation | author = Mat Rofa Bin Ismail | title = Algebra in Islamic Mathematics | encyclopedia = Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures | volume = 1 | year = 2008 | publisher = Springer | isbn = 9781402045592 | editor = Helaine Selin | editor-link = Helaine Selin | page=115 | edition=2nd}}</ref> ] wrote in his book ''al-Fakhrī'' that "negative quantities must be counted as terms".<ref name=Rashed /> In the 10th century, ] considered debts as negative numbers in ''A Book on What Is Necessary from the Science of Arithmetic for Scribes and Businessmen''.<ref name=Ismail /> | |||
;Ibn Turk and ''Logical Necessities in Mixed Equations'' | |||
By the 12th century, al-Karaji's successors were to state the general rules of signs and use them to solve ]s.<ref name=Rashed /> As ] writes: | |||
] (fl. 830) authored a manuscript entitled ''Logical Necessities in Mixed Equations'', which is very similar to al-Khwarzimi's ''Al-Jabr'' and was published at around the same time as, or even possibly earlier than, ''Al-Jabr''.<ref name="Boyer Ibn Turk">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977 | |||
<blockquote>the product of a negative number—''al-nāqiṣ''—by a positive number—''al-zāʾid''—is negative, and by a negative number is positive. If we subtract a negative number from a higher negative number, the remainder is their negative difference. The difference remains positive if we subtract a negative number from a lower negative number. If we subtract a negative number from a positive number, the remainder is their positive sum. If we subtract a positive number from an empty power (''martaba khāliyya''), the remainder is the same negative, and if we subtract a negative number from an empty power, the remainder is the same positive number.<ref name=Rashed /></blockquote> | |||
|quote=The ''Algebra'' of al-Khwarizmi usually is regarded as the first work on the subject, but a recent publication in Turkey raises some questions about this. A manuscript of a work by 'Abd-al-Hamid ibn-Turk, entitled "Logical Necessities in Mixed Equations," was part of a book on ''Al-jabr wa'l muqabalah'' which was evidently very much the same as that by al-Khwarizmi and was published at about the same time – possibly even earlier. The surviving chapters on "Logical Necessities" give precisely the same type of geometric demonstration as al-Khwarizmi's ''Algebra'' and in one case the same illustrative example x<sup>2</sup> + 21 = 10x. In one respect 'Abd-al-Hamad's exposition is more thorough than that of al-Khwarizmi for he gives geometric figures to prove that if the discriminant is negative, a quadratic equation has no solution. Similarities in the works of the two men and the systematic organization found in them seem to indicate that algebra in their day was not so recent a development as has usually been assumed. When textbooks with a conventional and well-ordered exposition appear simultaneously, a subject is likely to be considerably beyond the formative stage. Note the omission of Diophantus and Pappus, authors who evidently were not at first known in Arabia, although the Diophantine ''Arithmetica'' became familiar before the end of the tenth century.|page=234}}</ref> | |||
The manuscript gives exactly the same ] demonstration as is found in ''Al-Jabr'', and in one case the same example as found in ''Al-Jabr'', and even goes beyond ''Al-Jabr'' by giving a geometric proof that if the determinant is negative then the quadratic equation has no solution.<ref name="Boyer Ibn Turk" /> The similarity between these two works has led some historians to conclude that Islamic algebra may have been well developed by the time of al-Khwarizmi and 'Abd al-Hamid.<ref name="Boyer Ibn Turk" /> | |||
=== Double false position === | |||
;Abū Kāmil and al-Karkhi | |||
{{further|False position method}} | |||
Between the 9th and 10th centuries, the ] mathematician ] wrote a now-lost treatise on the use of double false position, known as the ''Book of the Two Errors'' (''Kitāb al-khaṭāʾayn''). The oldest surviving writing on double false position from the ] is that of ] (10th century), an ] mathematician from ], ]. He justified the technique by a formal, ]. Within the tradition of Golden Age Muslim mathematics, double false position was known as ''hisāb al-khaṭāʾayn'' ("reckoning by two errors"). It was used for centuries to solve practical problems such as commercial and juridical questions (estate partitions according to rules of ]), as well as purely recreational problems. The algorithm was often memorized with the aid of ], such as a verse attributed to ] and balance-scale diagrams explained by ] and ], who were each mathematicians of ] origin.<ref>{{Cite conference |conference=Eighth North African Meeting on the History of Arab Mathematics |last=Schwartz |first=R. K. |title=Issues in the Origin and Development of Hisab al-Khata'ayn (Calculation by Double False Position) |location=Radès, Tunisia |year=2004 |url=http://www.ub.edu/islamsci/Schwartz.pdf |access-date=2012-06-08 |archive-url=https://web.archive.org/web/20140516012137/http://www.ub.edu/islamsci/Schwartz.pdf |archive-date=2014-05-16}} {{cite web|url=http://facstaff.uindy.edu/~oaks/Biblio/COMHISMA8paper.doc |title=Issues in the Origin and Development of Hisab al-Khata'ayn (Calculation by Double False Position) |archive-url=https://web.archive.org/web/20110915195359/http://facstaff.uindy.edu/%7Eoaks/Biblio/COMHISMA8paper.doc |archive-date=2011-09-15 |url-status=dead |format=.doc}}</ref> | |||
Arabic mathematicians were also the first to treat ]s as ]ic objects.<ref name="ReferenceA">{{MacTutor|class=HistTopics|id=Arabic_mathematics|title=Arabic mathematics: forgotten brilliance?|year=1999}}</ref> The ]ian mathematician ] (c. 850–930) was the first to accept irrational numbers (often in the form of a ], ] or ]) as solutions to ]s or as ]s in an ].<ref name=Sesiano>Jacques Sesiano, "Islamic mathematics", p. 148, in {{citation|title=Mathematics Across Cultures: The History of Non-western Mathematics|first1=Helaine|last1=Selin|first2=Ubiratan|last2=D'Ambrosio|year=2000|publisher=]|isbn=1402002602}}</ref> He was also the first to solve three non-linear ] with three unknown ].<ref name=Berggren-518>{{Citation | first=J. Lennart | last=Berggren | title=The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A Sourcebook | chapter=Mathematics in Medieval Islam | publisher=Princeton University Press | year=2007 | isbn=9780691114859 | page=518}}</ref> | |||
== Influences == | |||
] (953–1029), also known as Al-Karaji, was the successor of ] (940–998) and he was the first to discover the solution to equations of the form ax<sup>2n</sup> + bx<sup>n</sup> = c.<ref name="Boyer al-Karkhi ax2n">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|isbn=0471543977|quote=Abu'l Wefa was a capable algebraist as well as a trigonometer. His successor al-Karkhi evidently used this translation to become an Arabic disciple of Diophantus – but without Diophantine analysis! In particular, to al-Karkhi is attributed the first numerical solution of equations of the form ax<sup>2n</sup> + bx<sup>n</sup> = c (only equations with positive roots were considered),|page=239}}</ref> Al-Karkhi only considered positive roots.<ref name="Boyer al-Karkhi ax2n"/> Al-Karkhi is also regarded as the first person to free algebra from ] operations and replace them with the type of ] operations which are at the core of algebra today. His work on algebra and ]s, gave the rules for arithmetic operations to manipulate polynomials. The ] F. Woepcke, in ''Extrait du Fakhri, traité d'Algèbre par Abou Bekr Mohammed Ben Alhacan Alkarkhi'' (Paris, 1853), praised Al-Karaji for being "the first who introduced the theory of algebraic ]". Stemming from this, Al-Karaji investigated ] and ].<ref>{{MacTutor|id=Al-Karaji|title=Abu Bekr ibn Muhammad ibn al-Husayn Al-Karaji}}</ref> | |||
The influence of medieval Arab-Islamic mathematics to the rest of the world is wide and profound, in both the realm of science and mathematics. The knowledge of the Arabs went into the western world through ] and ] during the translation movement. "The Moors (western Mohammedans from that part of North Africa once known as Mauritania) crossed over into Spain early in the seventh century, bringing with them the cultural resources of the Arab world".<ref name="Masters-2011a">{{Cite journal |last=Masters |first=Barry R. |date=2011-06-08 |title=Biomedical ethics, 7th edition David DeGrazia, Thomas A. Mappes, Jeffrey Brand-Ballard: 2010, Softcover, 732pp, ISBN-9780073407456 £171.15 McGraw-Hill Incorporated |url=http://dx.doi.org/10.1007/s00417-011-1640-x |journal=Graefe's Archive for Clinical and Experimental Ophthalmology |volume=250 |issue=1 |pages=159–160 |doi=10.1007/s00417-011-1640-x |issn=0721-832X}}</ref> In the 13th century, King ] established the ], in the ], where scholars translated numerous scientific and philosophical works from ] into ]. The translations included Islamic contributions to ], which helps European mathematicians and astronomers in their studies. European scholars such as ] (1114–1187) played a key role in translating and disseminating these works, thus making them accessible to a wider audience. Cremona is said to have translated into Latin "no fewer than 90 complete Arabic texts."<ref name="Masters-2011a" /> European mathematicians, building on the foundations laid by Islamic scholars, further developed practical trigonometry for applications in navigation, cartography, and celestial navigation, thus pushing forward the age of discovery and scientific revolution. The practical applications of trigonometry for navigation and astronomy became increasingly important during the Age of Exploration. | |||
] is one of the islamic mathematicians who made great contributions to the development of trigonometry. He "innovated new trigonometric functions, created a table of cotangents, and made some formulas in spherical trigonometry."<ref>{{Citation |title=Edited by |date=1972 |url=http://dx.doi.org/10.1016/s0049-237x(08)71546-5 |work=Contributions to Non-Standard Analysis |pages=iii |access-date=2023-12-15 |publisher=Elsevier}}</ref> These discoveries, together with his astronomical works which are praised for their accuracy, greatly advanced astronomical calculations and instruments. | |||
] manuscript from the 12th century depicting the ].]] | |||
] (1048–1131) was a Persian mathematician, astronomer, and poet, known for his work on algebra and geometry, particularly his investigations into the solutions of cubic equations. He was "the first in history to elaborate a geometrical theory of equations with degrees ≤ 3",<ref name="Rashed-2014">{{Cite book |last=Rashed |first=Roshdi |url=http://dx.doi.org/10.4324/9781315753867 |title=Classical Mathematics from Al-Khwarizmi to Descartes |date=2014-08-21 |publisher=Routledge |isbn=978-1-317-62239-0}}</ref> and has great influence on the work of Descartes, a French mathematician who is often regarded as the founder of analytical geometry. Indeed, "to read ]' Géométrie is to look upstream towards al-Khayyām and al-Ṭūsī; and downstream towards Newton, Leibniz, Cramer, Bézout and the Bernoulli brothers".<ref name="Rashed-2014" /> Numerous problems that appear in "La Géométrie" (Geometry) have foundations that date back to al-Khayyām. | |||
===Linear algebra=== | |||
In ] and ], ]s were known to ] mathematicians, possibly as early as the 7th century, when the Arabs got into contact with Indian or South Asian culture, and learned Indian mathematics and astronomy, including other aspects of ]. It has also been suggested that the idea came via China. The first magic squares of order 5 and 6 appear in an encyclopedia from ] ''circa'' 983 AD, the '']'' (''Encyclopedia of the Brethren of Purity''); simpler magic squares were known to several earlier Arab mathematicians.<ref name="Swaney">Swaney, Mark. .</ref> | |||
] ({{Langx|ar|أبو كامل شجاع بن أسلم بن محمد بن شجاع|links=no}}, also known as Al-ḥāsib al-miṣrī—lit. "The Egyptian Calculator") (c. 850 – c. 930), was studied algebra following the author of ''Algebra'', al-Khwārizmī. His ''Book of Algebra'' (Kitāb fī al-jabr wa al-muqābala) is "essentially a commentary on and elaboration of al-Khwārizmī's work; in part for that reason and in part for its own merit, the book enjoyed widespread popularity in the Muslim world".<ref name="Masters-2011b">{{Cite journal |last=Masters |first=Barry R. |date=2011-06-08 |title=Biomedical ethics, 7th edition David DeGrazia, Thomas A. Mappes, Jeffrey Brand-Ballard: 2010, Softcover, 732pp, ISBN-9780073407456 £171.15 McGraw-Hill Incorporated |url=http://dx.doi.org/10.1007/s00417-011-1640-x |journal=Graefe's Archive for Clinical and Experimental Ophthalmology |volume=250 |issue=1 |pages=159–160 |doi=10.1007/s00417-011-1640-x |issn=0721-832X}}</ref> It contains 69 problems, which is more than al-Khwārizmī who had 40 in his book.<ref name="Masters-2011b" /> Abū Kāmil's Algebra plays a significant role in shaping the trajectory of Western mathematics, particularly in its impact on the works of the Italian mathematician Leonardo of Pisa, widely recognized as Fibonacci. In his ''Liber Abaci'' (1202), Fibonacci extensively incorporated ideas from Arabic mathematicians, using approximately 29 problems from ''Book of Algebra'' with scarce modification.<ref name="Masters-2011b" /> | |||
The Arab mathematician ], who worked on magic squares around 1200 AD, attributed mystical properties to them, although no details of these supposed properties are known. There are also references to the use of magic squares in astrological calculations, a practice that seems to have originated with the Arabs.<ref name="Swaney"/> | |||
== Western historians' perception of the contribution of Arab mathematicians == | |||
===Geometric algebra=== | |||
Despite the fundamental works Arabic mathematicians have done on the development of Algebra and algebraic geometry, Western historians in the 18th and early 19th century still regarded it as a fact that ] and math were unique phenomena of the West. Even though some math contributions from Arab mathematicians are occasionally acknowledged, they are considered to be "outside history or only integrated in so far as it contributed to science, which is essentially European",<ref name="Rashed-1994">{{Cite journal |last=Rashed |first=Roshdi |date=1994 |title=The Development of Arabic Mathematics: Between Arithmetic and Algebra |url=http://dx.doi.org/10.1007/978-94-017-3274-1 |journal=Boston Studies in the Philosophy of Science |doi=10.1007/978-94-017-3274-1 |issn=0068-0346}}</ref> and just some technical innovations to the ] heritage rather than open up a completely new branch of mathematics. In the French philosopher ]'s work, Arabic math is merely "a reflection of ], combined with ] and Indian influences". And according to ], "Arabic science only reproduced the teachings received from Greek science". Besides being considered as merely some insignificant additions or reflections to the great tradition of Greek classical science, math works from Arabic mathematicians are also blamed for lacking rigor and too focused on practical applications and calculations, and this is why Western historians argued they could never reach the level of Greek mathematicians.<ref name="Rashed-1994" /> As ] wrote, Arabic math "in no way superseded the level attained by Diophantus". On the other hand, they perceived that Western mathematicians went into a very different way both in its method employed and ultimate purpose, "the hallmark of Western science in its Greek origins as well as in its modern renaissance, is its conformity to rigorous standards".<ref name="Rashed-1994" /> Thus, the perceived non-rigorous proof in Arabic mathematicians' book authorizes ] to exclude the Arabic period when he retraced the evolution of algebra.<ref name="Rashed-1994" /> And instead, the history of classical algebra is written as the work of the ] and the origin of algebraic geometry is traced back to Descartes, while Arabic mathematicians' contributions are ignored deliberately. In Rashed's words: "To justify the exclusion of science written in Arabic from the history of science, one invokes its absence of rigor, its calculatory appearance and its practical aims. Furthermore, strictly dependent on Greek science and, lastly, incapable of introducing experimental norms, scientists of that time were relegated to the role of conscientious guardians of the Hellenistic museum."<ref name="Rashed-1994" /> | |||
] (c. 1050–1123) wrote a book on Algebra that went beyond ''Al-Jabr'' to include equations of the third degree.<ref name="Boyer Omar Khayyam positive roots">{{Citation|first=Carl B.|last=Boyer|authorlink=Carl Benjamin Boyer|title=A History of Mathematics|edition=Second|publisher=John Wiley & Sons, Inc.|year=1991|chapter=The Arabic Hegemony|pages=241–242|isbn=0471543977}}: | |||
{{quote|Omar Khayyam (ca. 1050–1123), the "tent-maker," wrote an ''Algebra'' that went beyond that of al-Khwarizmi to include equations of third degree. Like his Arab predecessors, Omar Khayyam provided for quadratic equations both arithmetic and geometric solutions; for general cubic equations, he believed (mistakenly, as the sixteenth century later showed), arithmetic solutions were impossible; hence he gave only geometric solutions. The scheme of using intersecting conics to solve cubics had been used earlier by Menaechmus, Archimedes, and Alhazan, but Omar Khayyam took the praiseworthy step of generalizing the method to cover all third-degree equations (having positive roots). For equations of higher degree than three, Omar Khayyam evidently did not envision similar geometric methods, for space does not contain more than three dimensions, One of the most fruitful contributions of Arabic eclecticism was the tendency to close the gap between numerical and geometric algebra. The decisive step in this direction came much later with Descartes, but Omar Khayyam was moving in this direction when he wrote, "Whoever thinks algebra is a trick in obtaining unknowns has thought it in vain. No attention should be paid to the fact that algebra and geometry are different in appearance. Algebras are geometric facts which are proved."}}</ref> | |||
Omar Khayyám provided both arithmetic and geometric solutions for quadratic equations, but he only gave geometric solutions for general cubic equations since he mistakenly believed that arithmetic solutions were impossible.<ref name="Boyer Omar Khayyam positive roots" /> His method of solving cubic equations by using intersecting conics had been used by Menaechmus, Archimedes, and Alhazen, but Omar Khayyám generalized the method to cover all cubic equations with positive roots.<ref name="Boyer Omar Khayyam positive roots" /> He only considered positive roots and he did not go past the third degree.<ref name="Boyer Omar Khayyam positive roots" /> He also saw a strong relationship between Geometry and Algebra.<ref name="Boyer Omar Khayyam positive roots" /> | |||
In 18th century ] and ], the prevailing ] view was "East and West oppose each other not as geographical but as historical positivities",<ref name="Rashed-1994" /> which labeled "]" as the essence of the West, while the "Call of the ]" movement emerged in the 19th century was interpreted as "against Rationalism"<ref name="Rashed-1994" /> and a return to a more "spiritual and harmonious" lifestyle. Thus, the prevailing ] in that period was one of the main reasons why Arabic mathematicians were often ignored for their contributions, as people outside the West were considered to be lacking the necessary rationality and scientific spirit to made significant contributions to math and science. | |||
===Dynamic functional algebra=== | |||
In the 12th century, ] found algebraic and ] solutions to cubic equations and was the first to discover the ] of ].<ref name=Berggren/> His ''Treatise on Equations'' dealt with ]s up to the third degree. The treatise does not follow ]'s school of algebra, but instead represents "an essential contribution to another algebra which aimed to study curves by means of equations, thus inaugurating the beginning of ]." The treatise dealt with 25 types of equations, including twelve types of ]s and ]s, eight types of ]s with positive solutions, and five types of cubic equations which may not have positive solutions.<ref name=Sharaf>{{MacTutor|id=Al-Tusi_Sharaf|title=Sharaf al-Din al-Muzaffar al-Tusi}}</ref> He understood the importance of the ] of the cubic equation and used an early version of ]'s formula<ref>{{Citation | last1=Rashed | first1=Roshdi | last2=Armstrong | first2=Angela | year=1994 | title=The Development of Arabic Mathematics | publisher=] | isbn=0792325656 | pages=342–3}}</ref> to find algebraic solutions to certain types of cubic equations.<ref name=Berggren/> | |||
== Conclusion == | |||
Sharaf al-Din also developed the concept of a ]. In his analysis of | |||
The medieval Arab-Islamic world played a crucial role in shaping the trajectory of mathematics, with ]'s algebraic innovations serving as a cornerstone. The dissemination of Arabic mathematics to the West during the ], facilitated by cultural exchanges and translations, left a lasting impact on Western mathematical thought. Mathematicians like ], ], and ], with their contributions to ], ], and ], extended their influence beyond their time. Despite the foundational contributions of Arab mathematicians, Western historians in the 18th and early 19th centuries, influenced by ] views, sometimes marginalized these achievements. The East lacking rationality and scientific spirit perpetuated a biased perspective, hindering the recognition of the significant role played by Arabic mathematics in the development of algebra and other mathematical disciplines. Reevaluating the history of mathematics necessitates acknowledging the interconnectedness of diverse mathematical traditions and dispelling the notion of a uniquely European mathematical heritage. The contributions of Arab mathematicians, marked by practical applications and theoretical innovations, form an integral part of the rich tapestry of mathematical history, and deserves recognition. | |||
the equation <math>\ x^3 + d = bx^2</math> for example, he begins by changing the equation's form to <math>\ x^2 (b - x) = d</math>. He then states that the question of whether the equation has a solution depends on whether or not the “function” on the left side reaches the value <math>\ d</math>. To determine this, he finds a maximum value for the function. He proves that the maximum value occurs when <math>x = \frac{2b}{3}</math>, which gives the functional value <math>\frac{4b^3}{27}</math>. Sharaf al-Din then states that if this value is less than <math>\ d</math>, there are no positive solutions; if it is equal to <math>\ d</math>, then there is one solution at <math>x = \frac{2b}{3}</math>; and if it is greater than <math>\ d</math>, then there are two solutions, one between <math>\ 0</math> and <math>\frac{2b}{3}</math> and one between <math>\frac{2b}{3}</math> and <math>\ b</math>. This was the earliest form of dynamic ].<ref>{{Citation|last=Victor J. Katz|first=Bill Barton|title=Stages in the History of Algebra with Implications for Teaching|journal=Educational Studies in Mathematics|publisher=]|volume=66|issue=2|date=October 2007|doi=10.1007/s10649-006-9023-7|pages=185–201 |last2=Barton|first2=Bill}}</ref> | |||
== Other major figures == | |||
<!-- Image with unknown copyright status removed: ] commemorating ].]] --> | |||
* ] (fl. 830) (quadratics) | |||
* ] (d. after 864) | |||
* ] (826–901) | |||
* ] (before 858 – 929) | |||
* ] (c. 850 – c. 930) | |||
* ] (fl. 952) (arithmetic) | |||
* ] (d. 967) | |||
* ] (c. 940–1000) (centres of gravity) | |||
* ] (c. 965–1040) | |||
* ] (973–1048) (trigonometry) | |||
* ] (1048–1131) | |||
* ] (c. 1116–1196) | |||
* ] (1136–1206) | |||
* ] (c. 1380–1429) (decimals and estimation of the circle constant) | |||
== |
== Gallery == | ||
<gallery> | |||
In ], the essence of ] was known to ] in the 12th century, and it is possible that the algebraic tradition of Sharaf al-Dīn, as well as his predecessor ] and successor ], was known to 16th century European algebraists, of whom ] was the most important.<ref>{{citation|title=Historical Development of the Newton-Raphson Method|first=Tjalling J.|last=Ypma|journal=SIAM Review|volume=37|issue=4|date=December 1995|publisher=Society for Industrial and Applied Mathematics|pages=531–551 |doi=10.1137/1037125}}</ref> | |||
File:Gravure originale du compas parfait par Abū Sahl al-Qūhī.jpg|Engraving of ]'s perfect compass to draw conic sections | |||
File:Theorem of al-Haitham.JPG|The ] | |||
</gallery> | |||
== See also == | |||
A method algebraically equivalent to ] was also known to Sharaf al-Dīn. In the 15th century, his successor al-Kashi later used a form of Newton's method to numerically solve <math>\ x^P - N = 0</math> to find roots of <math>\ N</math>. In ], a similar method was later described by Henry Biggs in his ''Trigonometria Britannica'', published in 1633.<ref>{{citation|title=Historical Development of the Newton-Raphson Method|first=Tjalling J.|last=Ypma|journal=SIAM Review|volume=37|issue=4|date=December 1995|publisher=Society for Industrial and Applied Mathematics|pages=531–551 |doi=10.1137/1037125}}</ref> | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
== References == | |||
===Symbolic algebra=== | |||
{{Reflist|30em}} | |||
], a mathematician from ] specializing in ] during the 12th century, developed the modern symbolic ] for ], where the ] and ] are separated by a horizontal bar. This same fractional notation appeared soon after in the work of ] in the 13th century.{{Citation needed|date=May 2010}} | |||
== Sources ==<!--should be harvard, must be used in refs above--> | |||
] (1412–1482) was the last major medieval ] algebraist, who improved on the ] earlier used in the ] by ] in the 13th century<ref name=Qalasadi>{{MacTutor Biography|id=Al-Qalasadi|title= Abu'l Hasan ibn Ali al Qalasadi}}</ref> and by ] in the 12th century. In contrast to the syncopated notations of their predecessors, ] and ], which lacked symbols for ],<ref>{{Harv|Boyer|1991|loc="Revival and Decline of Greek Mathematics" p. 178}} "The chief difference between Diophantine syncopation and the modern algebraic notation is the lack of special symbols for operations and relations, as well as of the exponential notation."</ref> al-Qalasadi's algebraic notation was the first to have symbols for these functions and was thus "the first steps toward the introduction of algebraic symbolism." He represented ] using characters from the ].<ref name=Qalasadi/> | |||
{{refbegin|2}} | |||
* {{cite book |last=Berggren |first=J. Lennart |editor=Victor J. Katz |year=2007 |title=The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A Sourcebook|chapter=Mathematics in Medieval Islam|edition=2nd |publisher=] |location=Princeton, New Jersey |isbn=978-0-691-11485-9}} | |||
* {{Citation|last=Boyer|year=1991|first=Carl B.|author-link=Carl Benjamin Boyer|title=A History of Mathematics|chapter=Greek Trigonometry and Mensuration, and The Arabic Hegemony|edition=2nd|publisher=John Wiley & Sons|location=New York City|isbn=0-471-54397-7|url=https://archive.org/details/historyofmathema00boye}} | |||
* {{cite book |last=Katz|year=1993|first=Victor J. |title=A History of Mathematics: An Introduction|publisher=HarperCollins college publishers|isbn=0-673-38039-4}} | |||
* {{Citation |last=Nallino |first=C.A. |author-link=C.A. Nallino |contribution=Al-Ḥuwārismī e il suo rifacimento della Geografia di Tolomeo |pages=458–532 |title=Raccolta di scritti editi e inediti |volume=V |location=Rome |publisher=Istituto per l'Oriente |year=1939 |language=it}} | |||
* {{cite book |last=Rosen|first=Fredrick |title=The Algebra of Mohammed Ben Musa|date=1831|publisher=Kessinger Publishing |isbn=1-4179-4914-7 |url=https://archive.org/details/algebraofmohamme00khuwrich}} | |||
* {{cite book |last=Smith|year=1958|first=David E.|author-link=David Eugene Smith|title=History of Mathematics|publisher=Dover Publications|isbn=0-486-20429-4}} | |||
* {{Citation|last=Struik|year=1987|first=Dirk J.|author-link=Dirk Jan Struik|title=A Concise History of Mathematics|edition=4th rev.|publisher=Dover Publications|isbn=0-486-60255-9|url-access=registration|url=https://archive.org/details/concisehistoryof0000stru_m6j1}} | |||
{{refend}} | |||
==Further reading== | |||
The ] <math>\mathit{x}</math> now commonly ]s an unknown ]. Even though any letter can be used, <math>\mathit{x}</math> is the most common choice. This usage can be traced back to the ] word ''šay<nowiki>'</nowiki>'' شيء = “thing,” used in Arabic algebra texts such as the '']'', and was taken into ] with the pronunciation “šei,” which was written ''xei,'' and was soon habitually abbreviated to <math>\mathit{x}</math>. (The Spanish ] of “x” has changed since). Some sources say that this <math>\mathit{x}</math> is an abbreviation of ] ''causa,'' which was a translation of Arabic شيء. This started the habit of using letters to represent quantities in ]. In mathematics, an “] x” (<math>x\!</math>) is often used to avoid potential confusion with the multiplication symbol. | |||
{{Refbegin|2}} | |||
;Books on Islamic mathematics | |||
==Arithmetic== | |||
* {{cite book |last=Berggren |first=J. Lennart |title=Episodes in the Mathematics of Medieval Islam|year=1986|publisher=Springer-Verlag|location=New York|isbn=0-387-96318-9}} | |||
===Arabic numerals=== | |||
** Review: {{cite journal |last1=Toomer|first1=Gerald J.|author-link=Gerald J. Toomer|title=Episodes in the Mathematics of Medieval Islam |journal=] |volume=95 |issue=6 |year=1988 |doi=10.2307/2322777 |page=567 |publisher=Mathematical Association of America|last2=Berggren|first2=J. L.|jstor=2322777}} | |||
{{See also|Arabic numerals}} | |||
** Review: {{cite journal |last1=Hogendijk |first1=Jan P.| title=''Episodes in the Mathematics of Medieval Islam'' by J. Lennart Berggren |journal=Journal of the American Oriental Society |volume=109 |issue=4 |year=1989 |pages=697–698 |doi=10.2307/604119 |publisher=American Oriental Society|last2=Berggren|first2=J. L. |jstor=604119}} | |||
* {{cite book |last=Daffa' |first=Ali Abdullah al- |author-link=Ali Abdullah Al-Daffa |title=The Muslim contribution to mathematics |year=1977 |publisher=Croom Helm |location=London |isbn=0-85664-464-1}} | |||
* {{cite book |last=Ronan|year=1983|first=Colin A.|author-link=Colin Ronan|title=The Cambridge Illustrated History of the World's Science|publisher=Cambridge University Press|isbn=0-521-25844-8}} | |||
* {{cite book |last=Rashed|first=Roshdi |author-link=Roshdi Rashed |others=Translated by A. F. W. Armstrong |title=The Development of Arabic Mathematics: Between Arithmetic and Algebra |publisher=Springer|year=2001 |isbn=0-7923-2565-6}} | |||
* {{cite book |last=Youschkevitch |first=Adolf P. |author-link=Adolph Pavlovich Yushkevich |author2=Rozenfeld, Boris A. |title=Die Mathematik der Länder des Ostens im Mittelalter |year=1960|location=Berlin}} Sowjetische Beiträge zur Geschichte der Naturwissenschaft pp. 62–160. | |||
* {{cite book |last=Youschkevitch |first=Adolf P. |title=Les mathématiques arabes: VIII<sup>e</sup>–XV<sup>e</sup> siècles |others=translated by M. Cazenave and K. Jaouiche |publisher=Vrin |location=Paris |year=1976 |isbn=978-2-7116-0734-1}} | |||
; Book chapters on Islamic mathematics | |||
The ] system came to be known to both the ] mathematician ], whose book ''On the Calculation with Hindu Numerals'' written ''circa'' 825, and the ] mathematician ], who wrote four volumes, ''On the Use of the Indian Numerals'' (Ketab fi Isti'mal al-'Adad al-Hindi) ''circa'' 830, are principally responsible for the diffusion of the Indian system of numeration in the ] and the West . In the 10th century, ]ern mathematicians extended the decimal numeral system to include ] using ] notation, as recorded in a treatise by ] mathematician ] in 952–953. | |||
* Lindberg, D.C., and M. H. Shank, eds. ''The Cambridge History of Science. Volume 2: Medieval Science'' (Cambridge UP, 2013), chapters 2 and 3 mathematics in Islam. | |||
* {{cite book | first=Roger | last=Cooke | author-link=Roger Cooke (mathematician) | title=The History of Mathematics: A Brief Course | chapter=Islamic Mathematics | publisher=Wiley-Interscience | year=1997 | isbn=0-471-18082-3 | url=https://archive.org/details/historyofmathema0000cook }} | |||
In the ]—until early modern times—the Arabic numeral system was often only used by mathematicians. ] mostly used the ], and ] mostly used the ]. A distinctive "Western Arabic" variant of the symbols begins to emerge in ca. the 10th century in the ] and ], called the ''ghubar'' ("sand-table" or "dust-table") numerals, which is the direct ancestor to the modern Western Arabic numerals now used throughout the world.<ref>{{citation|title=The Origin of the Ghubār Numerals, or the Arabian Abacus and the Articuli|first=Solomon|last=Gandz|journal=]|volume=16|issue=2|date=November 1931|pages=393–424|doi=10.1086/346615}}</ref> | |||
; Books on Islamic science | |||
The first mentions of the numerals in the West are found in the '']'' of 976.<ref></ref> From the 980s, ] (later, Pope ]) began to spread knowledge of the numerals in Europe. Gerbert studied in ] in his youth, and he is known to have requested mathematical treatises concerning the ] from ] after he had returned to France. | |||
* {{cite book|first1=Ali Abdullah al-|last1=Daffa|first2=J.J.|last2=Stroyls|title=Studies in the exact sciences in medieval Islam|publisher=Wiley|location=New York|year=1984|isbn=0-471-90320-5}} | |||
* {{cite book|first=E. S.|last=Kennedy|author-link=Edward Stewart Kennedy|title=Studies in the Islamic Exact Sciences|year=1984|publisher=Syracuse Univ Press|isbn=0-8156-6067-7}} | |||
; Books on the history of mathematics | |||
], the ] scientist, wrote in 825 a treatise ''On the Calculation with Hindu Numerals'', which was translated into ], as ''Algoritmi de numero Indorum'', where "Algoritmi", the translator's rendition of the author's name gave rise to the word ] (Latin ''algorithmus'') with a meaning "calculation method". | |||
* {{cite book|last=Joseph|first=George Gheverghese|title=The Crest of the Peacock: Non-European Roots of Mathematics|edition=2nd|publisher=Princeton University Press|year=2000|isbn=0-691-00659-8|url=https://archive.org/details/crestofpeacockno00jose}} (Reviewed: {{cite journal|first1=Victor J.|last1=Katz|title='']'' by George Gheverghese Joseph|journal=The College Mathematics Journal|volume=23|issue=1|year=1992|pages=82–84|doi=10.2307/2686206|publisher=Mathematical Association of America|last2=Joseph|first2=George Gheverghese|jstor=2686206}}) | |||
* {{cite book|last=Youschkevitch|first=Adolf P.|title=Gesichte der Mathematik im Mittelalter|publisher=BG Teubner Verlagsgesellschaft|location=Leipzig|year=1964}} | |||
;Journal articles on Islamic mathematics | |||
Al-Hassār, a mathematician from the ] (]) specializing in ] during the 12th century, developed the modern symbolic ] for fractions, where the ] and ] are separated by a horizontal bar. The "dust ]s he used are also nearly identical to the digits used in the current Western Arabic numerals. These same digits and fractional notation appear soon after in the work of ] in the 13th century.{{Citation needed|date=May 2010}} | |||
* Høyrup, Jens. . ''Filosofi og Videnskabsteori på Roskilde Universitetscenter''. 3. Række: ''Preprints og Reprints'' 1987 Nr. 1. | |||
===Decimal fractions=== | |||
In discussing the origins of ], ] states that (p. 7):<ref>D.J. Struik, ''A Source Book in Mathematics 1200–1800'' (Princeton University Press, New Jersey, 1986). ISBN 0-691-02397-2</ref> | |||
<blockquote> | |||
"The introduction of decimal fractions as a common computational practice can be dated back to the ] pamphelet ''De Thiende'', published at ] in 1585, together with a French translation, ''La Disme'', by the Flemish mathematician ] (1548–1620), then settled in the Northern Netherlands. It is true that decimal fractions were used by the ] many centuries before Stevin and that the Persian astronomer ] used both decimal and ] fractions with great ease in his ''Key to arithmetic'' (Samarkand, early fifteenth century).<ref>P. Luckey, ''Die Rechenkunst bei Ğamšīd b. Mas'ūd al-Kāšī'' (Steiner, Wiesbaden, 1951).</ref>" | |||
</blockquote> | |||
While the ] mathematician ] claimed to have discovered decimal fractions himself in the 15th century, J. Lennart Berggrenn notes that he was mistaken, as decimal fractions were first used five centuries before him by the ]i mathematician ] as early as the 10th century.<ref name=Berggren-518/> | |||
===Real numbers=== | |||
The ] saw the acceptance of ], ], ] and ] numbers, first by ] and ], and then by Arabic mathematicians, who were also the first to treat ]s as algebraic objects,<ref name="ReferenceA"/> which was made possible by the development of algebra. Arabic mathematicians merged the concepts of "]" and "]" into a more general idea of ]s, and they criticized Euclid's idea of ]s, developed the theory of composite ratios, and extended the concept of number to ratios of continuous magnitude.<ref>{{citation|last=Matvievskaya|first=Galina|year=1987|title=The Theory of Quadratic Irrationals in Medieval Oriental Mathematics|journal=]|volume=500|pages=253–277 |doi=10.1111/j.1749-6632.1987.tb37206.x}}</ref> In his commentary on Book 10 of the ''Elements'', the ] mathematician ] (d. 874/884) examined and classified ]s and cubic irrationals. He provided definitions for rational and irrational magnitudes, which he treated as irrational numbers. He dealt with them freely but explains them in geometric terms as follows:<ref name=Matvievskaya-259>{{citation|last=Matvievskaya|first=Galina|year=1987|title=The Theory of Quadratic Irrationals in Medieval Oriental Mathematics|journal=]|volume=500|pages=253–277 |doi=10.1111/j.1749-6632.1987.tb37206.x}}</ref> | |||
{{quote|"It will be a rational (magnitude) when we, for instance, say 10, 12, 3%, 6%, etc., because its value is pronounced and expressed quantitatively. What is not rational is irrational and it is impossible to pronounce and represent its value quantitatively. For example: the roots of numbers such as 10, 15, 20 which are not squares, the sides of numbers which are not cubes ''etc.''"}} | |||
In contrast to Euclid's concept of magnitudes as lines, Al-Mahani considered integers and fractions as rational magnitudes, and square roots and ]s as irrational magnitudes. He also introduced an ]al approach to the concept of irrationality, as he attributes the following to irrational magnitudes:<ref name=Matvievskaya-259/> | |||
{{quote|"their sums or differences, or results of their addition to a rational magnitude, or results of subtracting a magnitude of this kind from an irrational one, or of a rational magnitude from it."}} | |||
The ]ian mathematician ] (c. 850–930) was the first to accept irrational numbers as solutions to ]s or as ]s in an ], often in the form of square roots, cube roots and ].<ref name=Sesiano/> In the 10th century, the ] mathematician Al-Hashimi provided general proofs for numbers (rather than geometric demonstrations) as he considered multiplication, division, etc. for ”lines.” Using this method, he provided the first proof for irrational numbers.<ref>{{citation|last=Matvievskaya|first=Galina|year=1987|title=The Theory of Quadratic Irrationals in Medieval Oriental Mathematics|journal=]|volume=500|pages=253–277 |doi=10.1111/j.1749-6632.1987.tb37206.x}}</ref> ] (900–971) provides a definition of rational and irrational magnitudes, stating that if a definite ] is:<ref>{{citation|last=Matvievskaya|first=Galina|year=1987|title=The Theory of Quadratic Irrationals in Medieval Oriental Mathematics|journal=]|volume=500|pages=253–277 |doi=10.1111/j.1749-6632.1987.tb37206.x}}</ref> | |||
{{quote|"contained in a certain given magnitude once or many times, then this (given) magnitude corresponds to a rational number. Each time when this (latter) magnitude comprises a half, or a third, or a quarter of the given magnitude (of the unit), or, compared with (the unit), comprises three, five, or three fifths, it is a rational magnitude. And, in general, each magnitude that corresponds to this magnitude (''i.e.'' to the unit), as one number to another, is rational. If, however, a magnitude cannot be represented as a multiple, a part (l/''n''), or parts (''m''/''n'') of a given magnitude, it is irrational, ''i.e.'' it cannot be expressed other than by means of roots."}} | |||
Many of these concepts were eventually accepted by European mathematicians some time after the ]. Al-Hassār, an Arabic mathematician from the ] (]) specializing in ] during the 12th century, developed the modern symbolic ] for fractions, where the ] and ] are separated by a horizontal bar. This same fractional notation appears soon after in the work of ] in the 13th century.{{Citation needed|date=May 2010}} | |||
===Number theory=== | |||
In ], ] solved problems involving ] using what is now called ]. In his ''Opuscula'', Ibn al-Haytham considers the solution of a system of congruences, and gives two general methods of solution. His first method, the canonical method, involved Wilson's theorem, while his second method involved a version of the ]. Another contribution to number theory is his work on ]s. In his ''Analysis and synthesis'', Ibn al-Haytham was the first to discover that every even perfect number is of the form 2<sup>''n''−1</sup>(2<sup>''n''</sup> − 1) where 2<sup>''n''</sup> − 1 is ], but he was not able to prove this result successfully (] later proved it in the 18th century).<ref>{{MacTutor Biography|id=Al-Haytham|title=Abu Ali al-Hasan ibn al-Haytham}}</ref> | |||
In the early 14th century, ] made a number of important contributions to number theory. His most impressive work in number theory is on ]s. In ''Tadhkira al-ahbab fi bayan al-tahabb'' ("Memorandum for friends on the proof of amicability") introduced a major new approach to a whole area of number theory, introducing ideas concerning ] and ] methods. In fact, al-Farisi's approach is based on the unique factorization of an ] into powers of ]s. | |||
==Geometry== | |||
] featuring ], from the title page of the ''De scientia motus orbis'' (Latin version with engraving, 1504). As in many medieval illustrations, the ] here is an icon of religion as well as science, in reference to God as the architect of creation.]] | |||
The successors of ] (born 780) undertook a systematic application of arithmetic to algebra, algebra to arithmetic, both to trigonometry, algebra to the ]ean theory of numbers, algebra to ], and geometry to algebra. This was how the creation of polynomial algebra, combinatorial analysis, numerical analysis, the numerical solution of equations, the new elementary theory of numbers, and the geometric construction of equations arose. | |||
] (born 820) conceived the idea of reducing geometrical problems such as duplicating the cube to problems in algebra. ] (born 953) completely freed algebra from geometrical operations and replaced them with the ]al type of operations which are at the core of algebra today. | |||
===Early Islamic geometry=== | |||
:''See also ]'' | |||
] (known as Thebit in ]) (born 836) contributed to a number of areas in mathematics, where he played an important role in preparing the way for such important mathematical discoveries as the extension of the concept of number to (]) ]s, ], theorems in ], ], and ]. An important geometrical aspect of Thabit's work was his book on the composition of ratios. In this book, Thabit deals with arithmetical operations applied to ratios of geometrical quantities. The Greeks had dealt with geometric quantities but had not thought of them in the same way as numbers to which the usual rules of arithmetic could be applied. By introducing arithmetical operations on quantities previously regarded as geometric and non-numerical, Thabit started a trend which led eventually to the generalization of the number concept. Another important contribution Thabit made to ] was his generalization of the ], which he extended from ] to all ]s in general, along with a general ].<ref name=Sayili>] (1960), "Thabit ibn Qurra's Generalization of the Pythagorean Theorem", '']'' '''51''' (1): 35–37</ref> | |||
In some respects, Thabit is critical of the ideas of Plato and Aristotle, particularly regarding motion. It would seem that here his ideas are based on an acceptance of using arguments concerning motion in his geometrical arguments. | |||
] ibn Thabit (born 908), who introduced a method of ] more general than that of ], and ] (born 940) were leading figures in a revival and continuation of Greek higher geometry in the Islamic world. These mathematicians, and in particular ] (Alhazen), studied ] and investigated the optical properties of mirrors made from ]s (see ]). | |||
Astronomy, time-keeping and ] provided other motivations for geometrical and trigonometrical research. For example Ibrahim ibn Sinan and his grandfather ] both studied curves required in the construction of sundials. ] and ] pioneered ] in order to solve difficult problems in ]. For example, to predict the first visibility of the moon, it was necessary to describe its motion with respect to the ], and this problem demands fairly sophisticated spherical geometry. Finding the direction of ] (]) and the time for ] prayers and ] are what led to Muslims developing spherical geometry.<ref name=Gingerich>{{Citation |last=Gingerich |first=Owen |date = April 1986|url=http://faculty.kfupm.edu.sa/PHYS/alshukri/PHYS215/Islamic_astronomy.htm |title=Islamic astronomy |journal=] |volume=254 |issue=10 |page=74 |accessdate=2008-05-18}}</ref><ref name=Tabatabai/> | |||
===Algebraic and analytic geometry=== | |||
] for the 1940 edition of the '']''.]] | |||
In the early 11th century, ] (Alhazen) was able to solve by purely algebraic means certain cubic equations, and then to interpret the results geometrically.<ref>Kline, M. (1972), ''Mathematical Thought from Ancient to Modern Times'', Volume 1, p. 193, ]</ref> Subsequently, ] discovered the general method of solving ]s by intersecting a parabola with a circle.<ref>Kline, M. (1972), ''Mathematical Thought from Ancient to Modern Times'', Volume 1, pp. 193–195, ]</ref> | |||
] (1048–1122) was a ] mathematician, as well as a poet. Along with his fame as a poet, he was also famous during his lifetime as a mathematician, well known for inventing the general method of solving ]s by intersecting a parabola with a circle. In addition he discovered the ], and authored criticisms of ]'s theories of ] which made their way to England, where they contributed to the eventual development of ]. Omar Khayyam also combined the use of trigonometry and ] to provide methods of solving algebraic equations by geometrical means. His work marked the beginnings of ]<ref name="ReferenceA"/><ref>R. Rashed (1994). ''The development of Arabic mathematics: between arithmetic and algebra''. London.</ref> and ].<ref name=Cooper/> | |||
In a paper written by Khayyam before his famous algebra text ''Treatise on Demonstration of Problems of Algebra'', he considers the problem: ''Find a point on a quadrant of a circle in such manner that when a normal is dropped from the point to one of the bounding radii, the ratio of the normal's length to that of the radius equals the ratio of the segments determined by the foot of the normal.'' Khayyam shows that this problem is equivalent to solving a second problem: ''Find a right triangle having the property that the hypotenuse equals the sum of one leg plus the altitude on the hypotenuse.'' This problem in turn led Khayyam to solve the cubic equation x<sup>3</sup> + 200x = 20x<sup>2</sup> + 2000 and he found a positive root of this cubic by considering the intersection of a rectangular hyperbola and a circle. An approximate numerical solution was then found by interpolation in trigonometric tables. Perhaps even more remarkable is the fact that Khayyam states that the solution of this cubic requires the use of conic sections and that it cannot be solved by compass and straightedge, a result which would not be proved for another 750 years. | |||
His ''Treatise on Demonstration of Problems of Algebra'' contained a complete classification of cubic equations with geometric solutions found by means of intersecting conic sections. In fact Khayyam gives an interesting historical account in which he claims that the Greeks had left nothing on the theory of cubic equations. Indeed, as Khayyam writes, the contributions by earlier writers such as al-Mahani and ] were to translate geometric problems into algebraic equations (something which was essentially impossible before the work of ]). However, Khayyam himself seems to have been the first to conceive a general theory of cubic equations. | |||
Omar Khayyám saw a strong relationship between geometry and algebra, and was moving in the right direction when he helped to close the gap between numerical and geometric algebra<ref name="Boyer Omar Khayyam positive roots"/> with his geometric solution of the general ]s,<ref name=Cooper>Glen M. Cooper (2003). "Omar Khayyam, the Mathmetician", ''The Journal of the American Oriental Society'' '''123'''.</ref> but the decisive step in ] came later with ].<ref name="Boyer Omar Khayyam positive roots">{{Citation|last=Boyer|authorlink=Carl Benjamin Boyer|title=|year=1991|chapter=The Arabic Hegemony|pages=241–242|quote=Omar Khayyam (ca. 1050–1123), the "tent-maker," wrote an ''Algebra'' that went beyond that of al-Khwarizmi to include equations of third degree. Like his Arab predecessors, Omar Khayyam provided for quadratic equations both arithmetic and geometric solutions; for general cubic equations, he believed (mistakenly, as the sixteenth century later showed), arithmetic solutions were impossible; hence he gave only geometric solutions. The scheme of using intersecting conics to solve cubics had been used earlier by Menaechmus, Archimedes, and Alhazan, but Omar Khayyam took the praiseworthy step of generalizing the method to cover all third-degree equations (having positive roots). For equations of higher degree than three, Omar Khayyam evidently did not envision similar geometric methods, for space does not contain more than three dimensions, One of the most fruitful contributions of Arabic eclecticism was the tendency to close the gap between numerical and geometric algebra. The decisive step in this direction came much later with Descartes, but Omar Khayyam was moving in this direction when he wrote, "Whoever thinks algebra is a trick in obtaining unknowns has thought it in vain. No attention should be paid to the fact that algebra and geometry are different in appearance. Algebras are geometric facts which are proved."}}</ref> | |||
Persian mathematician ] (born 1135) did not follow the general development that came through ]'s school of algebra but rather followed Khayyam's application of algebra to geometry. He wrote a treatise on cubic equations, entitled ''Treatise on Equations'', which represents an essential contribution to another algebra which aimed to study curves by means of equations, thus inaugurating the study of ].<ref name=Sharaf/> | |||
===Non-Euclidean geometry=== | |||
] commemorated on an Iranian stamp upon the 700th anniversary of his death.]] | |||
In the early 11th century, ] (Alhazen) made the first attempt at proving the ] ], the fifth ] in ], using a ],<ref>{{Harv|Eder|2000}}</ref> where he introduced the concept of ] and ] into geometry.<ref>{{Harv|Katz|1998|p=269}}: {{quote|In effect, this method characterized parallel lines as lines always equidisant from one another and also introduced the concept of motion into geometry.}}</ref> He formulated the ], which Boris Abramovich Rozenfeld names the "Ibn al-Haytham–Lambert quadrilateral",<ref name=Rozenfeld>{{Harv|Rozenfeld|1988|p=65}}</ref> and his attempted proof also shows similarities to ].<ref name=Smith>{{Harv|Smith|1992}}</ref> | |||
In the late 11th century, ] made the first attempt at formulating a ] ] as an alternative to the ] ],<ref>Victor J. Katz (1998), ''History of Mathematics: An Introduction'', p. 270, ], ISBN 0321016181: {{quote|"In some sense, his treatment was better than ibn al-Haytham's because he explicitly formulated a new postulate to replace Euclid's rather than have the latter hidden in a new definition."}}</ref> and he was the first to consider the cases of ] and ], though he excluded the latter.<ref name=Rosenfeld>Boris A. Rosenfeld and Adolf P. Youschkevitch (1996), "Geometry", in Roshdi Rashed, ed., '']'', Vol. 2, pp. 447–494 , ], London and New York: {{quote|"Khayyam's postulate had excluded the case of the hyperbolic geometry whereas al-Tusi's postulate ruled out both the hyperbolic and elliptic geometries."}}</ref> | |||
In ''Commentaries on the difficult postulates of Euclid's book'' Khayyam made a contribution to non-Euclidean geometry, although this was not his intention. In trying to prove the parallel postulate he accidentally proved properties of figures in non-Euclidean geometries. Khayyam also gave important results on ratios in this book, extending Euclid's work to include the multiplication of ratios. The importance of Khayyam's contribution is that he examined both Euclid's definition of equality of ratios (which was that first proposed by {{dn|Eudoxus}}) and the definition of equality of ratios as proposed by earlier Islamic mathematicians such as al-Mahani which was based on ]s. Khayyam proved that the two definitions are equivalent. He also posed the question of whether a ratio can be regarded as a number but leaves the question unanswered. | |||
The ] was first considered by Omar Khayyam in the late 11th century in Book I of ''Explanations of the Difficulties in the Postulates of Euclid''.<ref name=Rozenfeld>Boris Abramovich Rozenfelʹd (1988), ''A History of Non-Euclidean Geometry: Evolution of the Concept of a Geometric Space'', p. 65. Springer, ISBN 0387964584.</ref> Unlike many commentators on Euclid before and after him (including of course Saccheri), Khayyam was not trying to prove the ] as such but to derive it from an equivalent postulate he formulated from "the principles of the Philosopher" (]): | |||
:Two convergent straight lines intersect and it is impossible for two convergent straight lines to diverge in the direction in which they converge.<ref>Boris A Rosenfeld and Adolf P Youschkevitch (1996), ''Geometry'', p. 467 in Roshdi Rashed, Régis Morelon (1996), ''Encyclopedia of the history of Arabic science'', Routledge, ISBN 0415124115.</ref> | |||
Khayyam then considered the three cases right, obtuse, and acute that the summit angles of a Saccheri quadrilateral can take and after proving a number of theorems about them, he (correctly) refuted the obtuse and acute cases based on his postulate and hence derived the classic postulate of Euclid. It wasn't until 600 years later that ] made an advance on the understanding of this quadrilateral in his book ''Euclide restituo'' (1680, 1686), when he used it to prove that if three points are equidistant on the base AB and the summit CD, then AB and CD are everywhere equidistant. ] himself based the whole of his long, heroic and ultimately flawed proof of the parallel postulate around the quadrilateral and its three cases, proving many theorems about its properties along the way. | |||
In 1250, ], in his ''Al-risala al-shafiya'an al-shakk fi'l-khutut al-mutawaziya'' (''Discussion Which Removes Doubt about Parallel Lines''), wrote detailed critiques of the ] ] and on ]'s attempted proof a century earlier. Nasir al-Din attempted to derive a ] of the parallel postulate.<ref name=Katz/> He was one of the first to consider the cases of ] and ], though he ruled out both of them.<ref name=Rosenfeld/> | |||
His son, Sadr al-Din (sometimes known as "Pseudo-Tusi"), wrote a book on the subject in 1298, based on al-Tusi's later thoughts, which presented one of the earliest arguments for a ] hypothesis equivalent to the parallel postulate.<ref name=Katz/><ref>Boris A. Rosenfeld and Adolf P. Youschkevitch (1996), "Geometry", in Roshdi Rashed, ed., '']'', Vol. 2, pp. 447–494 , ], London and New York: {{quote|"In ''Pseudo-Tusi's Exposition of Euclid'', another statement is used instead of a postulate. It was independent of the Euclidean postulate V and easy to prove. He essentially revised both the Euclidean system of axioms and postulates and the proofs of many propositions from the ''Elements''."}}</ref> Sadr al-Din's work was published in Rome in 1594 and was studied by European geometers. This work marked the starting point for ]'s work on the subject, and eventually the development of modern ].<ref name=Katz>Victor J. Katz (1998), ''History of Mathematics: An Introduction'', pp. 270–271, ], ISBN 0321016181: <blockquote>"But in a manuscript probably written by his son Sadr al-Din in 1298, based on Nasir al-Din's later thoughts on the subject, there is a new argument based on another hypothesis, also equivalent to Euclid's, The importance of this latter work is that it was published in Rome in 1594 and was studied by European geometers. In particular, it became the starting point for the work of Saccheri and ultimately for the discovery of non-Euclidean geometry."<blockquote></ref> A proof from Sadr al-Din's work was quoted by ] and Saccheri in the 17th and 18th centuries. They both derived their proofs of the parallel postulate from Sadr al-Din's work, while Saccheri also derived his ] from Sadr al-Din, who himself based it on his father's work.<ref>Boris A. Rosenfeld and Adolf P. Youschkevitch (1996), "Geometry", in Roshdi Rashed, ed., '']'', Vol. 2, pp. 447–494 , ], London and New York: {{quote|"His book published in Rome considerably influenced the subsequent development of the theory of parallel lines. Indeed, J. Wallis (1616–1703) included a Latin translation of the proof of postulate V from this book in his own writing ''On the Fifth Postulate and the Fifth Definition from Euclid's Book 6'' (''De Postulato Quinto et Definitione Quinta lib. 6 Euclidis'', 1663). Saccheri quited this proof in his ''Euclid Cleared of all Stains'' (''Euclides ab omni naevo vindicatus'', 1733). It seems possible that he borrowed the idea of considering the three hypotheses about the upper angles of the 'Saccheri quadrangle' from Pseudo-Tusi. The latter inserted the exposition of this subject into his work, taking it from the writings of al-Tusi and Khayyam."}}</ref> | |||
The theorems of ] (Alhazen), ] and ] on ]s, including the ] and ], were the first theorems on ] and ], and along with their alternative postulates, such as ], these works marked the beginning of ] and had a considerable influence on its development among later European geometers, including ], ], ], ], and ].<ref>Boris A. Rosenfeld and Adolf P. Youschkevitch (1996), "Geometry", in Roshdi Rashed, ed., '']'', Vol. 2, pp. 447–494 , ], London and New York: {{quote|"Three scientists, Ibn al-Haytham, Khayyam and al-Tusi, had made the most considerable contribution to this branch of geometry whose importance came to be completely recognized only in the ninteenth century. In essence their propositions concerning the properties of quadrangles which they considered assuming that some of the angles of these figures were acute of obtuse, embodied the first few theorems of the hyperbolic and the elliptic geometries. Their other proposals showed that various geometric statements were equivalent to the Euclidean postulate V. It is extremely important that these scholars established the mutual connection between tthis postulate and the sum of the angles of a triangle and a quadrangle. By their works on the theory of parallel lines Arab mathematicians directly influenced the relevant investiagtions of their European couterparts. The first European attempt to prove the postulate on parallel lines – made by Witelo, the Polish scientists of the thirteenth century, while revising Ibn al-Haytham's '']'' (''Kitab al-Manazir'') – was undoubtedly prompted by Arabic sources. The proofs put forward in the fourteenth century by the Jewish scholar Levi ben Gerson, who lived in southern France, and by the above-mentioned Alfonso from Spain directly border on Ibn al-Haytham's demonstration. Above, we have demonstrated that ''Pseudo-Tusi's Exposition of Euclid'' had stimulated borth J. Wallis's and G. Saccheri's studies of the theory of parallel lines."}}</ref> | |||
==Trigonometry== | |||
The early ] on ] were translated and expanded in the ] by ] and ] mathematicians, who enunciated a large number of theorems which freed the subject of trigonometry from dependence upon the complete ], as was the case in Hellenistic mathematics due to the application of ]. According to E. S. Kennedy, it was after this development in Islamic mathematics that "the first real trigonometry emerged, in the sense that only then did the object of study become the ] or plane ], its sides and ]s."<ref>{{citation|first=E. S.|last=Kennedy|title=The History of Trigonometry|journal=31st Yearbook|publisher=National Council of Teachers of Mathematics, Washington DC|year=1969}} (] {{citation|first=Syed Nomanul|last=Haq|title=The Indian and Persian background|pages=60–3}}, in {{citation|title=History of Islamic Philosophy|first=Oliver Leaman|last=]|year=1996|publisher=]|isbn=0415131596|pages=52–70}})</ref> Another important development was the subject's separation from astronomy. All works on trigonometry up until the 12th century treated it mainly as an adjunct to astronomy; the first treatment of trigonometry as a subject in its own right was by ] in the 13th century.<ref name=trigonometry>{{cite web|title=trigonometry|url=http://www.britannica.com/EBchecked/topic/605281/trigonometry|publisher='']''|accessdate=2008-07-21}}</ref> | |||
===Trigonometric functions=== | |||
In the early 9th century, {{Unicode|]}} (c. 780–850) produced tables for the ] of sines and cosine,<ref name=Kennedy-1956>{{citation|last=Kennedy|first=E.S.|title=A Survey of Islamic Astronomical Tables; Transactions of the American Philosophical Society| year=1956|location=]| publisher=]|volume=46|issue=2|pages=26–9}}</ref> and the first tables for tangents.<ref name=MacTutor-Khwarizmi>{{MacTutor|id=Al-Khwarizmi|name=Abu Ja'far Muhammad ibn Musa Al-Khwarizmi}}</ref> In 830, ] produced the first tables of cotangents as well as tangents.<ref name=trigonometry/><ref name=Sesiano-157/> ] (853–929) discovered the reciprocal functions of secant and cosecant, and produced the first table of cosecants, which he referred to as a "table of shadows" (in reference to the shadow of a ]), for each degree from 1° to 90°.<ref name=trigonometry/> By the 10th century, in the work of ] (959–998), Muslim mathematicians were using all six trigonometric functions, and had sine tables in 0.25° increments, to 8 decimal places of accuracy, as well as accurate tables of ] values. | |||
] (1393–1449) gives trigonometric tables of values of the sine function to four ] digits (equivalent to 8 decimal places) for each 1° of argument with differences to be added for each 1/60 of 1°.<ref name=Kashi>{{MacTutor|id=Al-Kashi|title=Ghiyath al-Din Jamshid Mas'ud al-Kashi}}</ref> In one of his ], he correctly computed 2π to 9 ] digits.<ref>''Al-Kashi'', author: Adolf P. Youschkevitch, chief editor: Boris A. Rosenfeld, p. 256</ref> In order to determine sin 1°, al-Kashi discovered the following ] often attributed to ] in the 16th century:<ref>{{citation|title=Sherlock Holmes in Babylon and Other Tales of Mathematical History|last=Marlow Anderson, Victor J. Katz|first=Robin J. Wilson|publisher=]|year=2004|isbn=0883855461|page=139}}</ref> | |||
:<math>\sin 3 \phi = 3 \sin \phi - 4 \sin^3 \phi\,.</math> | |||
Al-Kashi, alongside his colleague ] (1394–1449), gave accurate tables of sines and tangents correct to 8 decimal places. ] (1526–1585) contributed to trigonometry in his ''Sidrat al-Muntaha'', in which he was the first ] to compute a highly accurate numeric value for ] 1°. He discusses the values given by his predecessors, explaining how ] (ca. 150) used an approximate method to obtain his value of sin 1° and how Abū al-Wafā, ] (ca. 1000), al-Kashi, ] (1337–1412), Ulugh Beg and Mirim Chelebi improved on the value. Taqi al-Din then solves the problem to obtain the value of sin 1° to a precision of 8 sexagesimals (the equivalent of 14 decimals):{{Citation needed|date=May 2010}} | |||
:<math> \sin 1^\circ = 1^P 2' 49'' 43''' 11'''' 14''''' 44''''''16''''''' \ (= 1/60 + 2/60^2 + 49/60^3 + \cdots)\,.</math> | |||
===Laws and identities=== | |||
] (853–929) formulated a number of important trigonometrical relationships such as: | |||
:<math>\tan a = \frac{\sin a}{\cos a}</math> | |||
:<math>\sec a = \sqrt{1 + \tan^2 a }</math> | |||
Although there are several candidates for the title of discoverer,<ref>''Also the 'sine law' (of geometry and trigonometry, applicable to sperical trigonometry) is attributed, among others, to Alkhujandi. (The three others are Abul Wafa Bozjani, Nasiruddin Tusi and Abu Nasr Mansur).'' Razvi, Syed Abbas Hasan (1991) ''A history of science, technology, and culture in Central Asia, Volume 1'' University of Peshawar, Peshawar, Pakistan, page 358, </ref><ref>Bijli suggests that three mathematicians are in contention for the honor, Alkhujandi, Abdul-Wafa and Mansur, leaving out Nasiruddin Tusi. Bijli, Shah Muhammad and Delli, Idarah-i Adabiyāt-i (2004) ''Early Muslims and their contribution to science: ninth to fourteenth century'' Idarah-i Adabiyat-i Delli, Delhi, India, page 44, </ref> in the 10th century, ] significantly contributed to the discovery and use of the ] for ]:<ref name=Sesiano-157>Jacques Sesiano, "Islamic mathematics", p. 157, in {{citation|title=Mathematics Across Cultures: The History of Non-western Mathematics|first1=Helaine|last1=Selin|first2=Ubiratan|last2=D'Ambrosio|year=2000|publisher=]|isbn=1402002602}}</ref> | |||
:<math>\frac{\ a}{\sin A} = \frac{\ b}{\sin B} = \frac{c}{\sin C}.</math> | |||
Abū al-Wafā' also developed the following trigonometric formula: | |||
:<math> \sin 2x = 2 \sin x \cos x \ </math> | |||
Abū al-Wafā also established the angle addition identities, e.g. sin (''a'' ± ''b'').<ref name=Sesiano-157/> | |||
:<math>\sin(a \pm b) = \sin a \cos b \pm \cos a \sin b</math> | |||
Also in the late 10th and early 11th centuries, the Egyptian astronomer ] performed many careful trigonometric calculations and demonstrated the following formula: | |||
:<math>\cos a \cos b = \frac{\cos(a+b) + \cos(a-b)}{2}</math> | |||
Also in the 11th century, ]'s ''The book of unknown arcs of a sphere'' introduced the general law of sines.<ref name="MacTutor Al-Jayyani"/> In the 13th century, ], in his ''On the Sector Figure'', stated the law of sines for plane and spherical triangles, discovered the ] for spherical triangles, and provided proofs for these laws.<ref name=Berggren-518/> ] (1393–1449) provided the first explicit statement of the ] in a form suitable for ].<ref name=Kashi/> As such, the law of cosines is known the ] in France. | |||
===Spherical trigonometry=== | |||
Hellenistic methods dealing with spherical triangles were known, particularly the method of ], who developed ] to deal with spherical problems.<ref>{{MacTutor|id=Menelaus|title=Menelaus of Alexandria}} "Book 3 deals with spherical trigonometry and includes Menelaus's theorem."</ref><ref name="Boyer Menelaus of Alexandria">{{Citation|last=Boyer|authorlink=Carl Benjamin Boyer|title=|year=1991|chapter=Greek Trigonometry and Mensuration|quote=In Book I of this treatise Menelaus establishes a basis for spherical triangles analogous to that of Euclid I for plane triangles. Included is a theorem without Euclidean analogue – that two spherical triangles are congruent if corresponding angles are equal (Menelaus did not distinguish between congruent and symmetric spherical triangles); and the theorem A + B + C > 180° is established. The second book of the ''Sphaerica'' describes the application of spherical geometry to astronomical phenomena and is of little mathematical interest. Book III, the last, contains the well known "theorem of Menelaus" as part of what is essentially spherical trigonometry in the typical Greek form – a geometry or trigonometry of chords in a circle. In the circle in Fig. 10.4 we should write that chord AB is twice the sine of half the central angle AOB (multiplied by the radius of the circle). Menelaus and his Greek successors instead referred to AB simply as the chord corresponding to the arc AB. If BOB' is a diameter of the circle, then chord A' is twice the cosine of half the angle AOB (multiplied by the radius of the circle).|page=163}}</ref> However, E. S. Kennedy points out that while it was possible in pre-lslamic mathematics to compute the magnitudes of a spherical figure, in principle, by use of the table of chords and Menelaus' theorem, the application of the theorem to spherical problems was very difficult in practice.<ref>{{citation|first=E. S.|last=Kennedy|title=The History of Trigonometry|journal=31st Yearbook|publisher=National Council of Teachers of Mathematics, Washington DC|year=1969|page=337}} (] {{citation|first=Syed Nomanul|last=Haq|title=The Indian and Persian background|page=68}}, in {{citation|title=History of Islamic Philosophy|first=Oliver Leaman|last=]|year=1996|publisher=]|isbn=0415131596|pages=52–70}})</ref> In order to observe holy days on the ] in which timings were determined by ], astronomers initially used Menelaus' method to calculate the place of the ] and ]s, though this method proved to be clumsy and difficult. It involved setting up two intersecting ]s; by applying Menelaus' theorem it was possible to solve one of the six sides, but only if the other five sides were known. To tell the time from the ]'s ], for instance, repeated applications of Menelaus' theorem were required. For medieval ], there was an obvious challenge to find a simpler trigonometric method.<ref name=Gingerich/> | |||
In the early 9th century, ] was an early pioneer in ] and wrote a treatise on the subject.<ref name=MacTutor-Khwarizmi/> In the 10th century, ] discovered the ] for spherical trigonometry.<ref name=Sesiano-157/> In the 11th century, ] (989–1079) of ] wrote ''The book of unknown arcs of a sphere'', which is considered "the first treatise on spherical trigonometry" in its modern form.<ref name="MacTutor Al-Jayyani">{{MacTutor|id=Al-Jayyani|title=Abu Abd Allah Muhammad ibn Muadh Al-Jayyani}}</ref> It "contains formulae for ], the general law of sines, and the solution of a ] by means of the polar ]." This treatise later had a "strong influence on European mathematics", and his "definition of ]s as numbers" and "method of solving a spherical triangle when all sides are unknown" are likely to have influenced ].<ref name="MacTutor Al-Jayyani"/> In the 13th century, ] developed spherical trigonometry into its present form,<ref name=trigonometry/> and listed the six distinct cases of a right-angled triangle in spherical trigonometry.<ref name=Berggren-518/> In his ''On the Sector Figure'', he also stated the law of sines for plane and spherical triangles, and discovered the ] for spherical triangles.<ref name=Berggren-518/> | |||
===Other advances=== | |||
The method of ], which was unknown in the ] world, was also first developed by Muslim mathematicians, who applied it to practical uses such as ]<ref>] (1996), "Engineering", in Roshdi Rashed, ''Encyclopedia of the History of Arabic Science'', Vol. 3, pp. 751–795 </ref> and ], as described by ] in the early 11th century. Biruni employed triangulation techniques to measure the size of the Earth and the distances between places (see '']'' section).<ref>{{MacTutor|id=Al-Biruni|title=Abu Arrayhan Muhammad ibn Ahmad al-Biruni}}</ref> | |||
In the late 11th century, ] (1048–1131) solved ]s using approximate numerical solutions found by interpolation in trigonometric tables (see '']'' and '']'' sections). ] (1393–1449) provided the first explicit statement of the ] in a form suitable for triangulation.<ref name=Kashi/> | |||
==Calculus== | |||
] (Alhazen), author of the '']''.]] | |||
===Integral calculus=== | |||
Around 1000 AD, ], using ], found a ] for the sum of ] ].<ref>Victor J. Katz (1998). ''History of Mathematics: An Introduction'', pp. 255–259. ]. ISBN 0321016181.</ref> The ] of mathematics, F. Woepcke,<ref>F. Woepcke (1853). ''Extrait du Fakhri, traité d'Algèbre par Abou Bekr Mohammed Ben Alhacan Alkarkhi''. Paris.</ref> praised Al-Karaji for being "the first who introduced the ] of ]ic ]." Shortly afterwards, ] (known as Alhazen in the West), an ]i mathematician working in ], was the first mathematician to derive the formula for the sum of the ]s, and using an early ] by ], he developed a method for determining the general formula for the sum of any integral powers. He used his result on sums of integral powers to perform an ], in order to find the volume of a ]. He was thus able to find the ]s for ]s up to the ], and came close to finding a general formula for the integrals of any polynomials. This was fundamental to the development of ] and integral calculus. His results were repeated by the ] mathematicians Abu-l-Hasan ibn Haydur (d. 1413) and Abu Abdallah ibn Ghazi (1437–1514), by ] (c. 1380–1429) in ''The Calculator's Key'', and by the ] of the ] in the 15th–16th centuries.<ref name=Katz>Victor J. Katz (1995), "Ideas of Calculus in Islam and India", ''Mathematics Magazine'' '''68''' (3): 163–174 </ref> | |||
===Differential calculus=== | |||
In the 12th century, the ] mathematician ] was the first to discover the ] of ], an important result in ].<ref name=Berggren>J. L. Berggren (1990), "Innovation and Tradition in Sharaf al-Din al-Tusi's Muadalat", ''Journal of the American Oriental Society'' '''110''' (2): 304–9</ref> His ''Treatise on Equations'' developed concepts related to ], such as the ] function and the ] of curves, in order to solve cubic equations which may not have positive solutions. | |||
For example, in order to solve the equation <math>\ x^3 + a = bx</math> with a and b positives, al-Tusi finds the maximum point of the curve <math>\ bx - x^3 = a</math>. He uses the derivative of the function to find that the maximum point occurs at <math>x = \sqrt{\frac{b}{3}}</math>, and then finds the maximum value for y at <math>2(\frac{b}{3})^\frac{3}{2}</math> by substituting <math>x = \sqrt{\frac{b}{3}}</math> back into <math>\ y = bx - x^3</math>. He finds that the equation <math>\ bx - x^3 = a</math> has a positive solution if <math>a \le 2(\frac{b}{3})^\frac{3}{2}</math>, and al-Tusi thus deduces that the equation has a positive root if <math>D = \frac{b^3}{27} - \frac{a^2}{4} \ge 0</math>, where <math>D</math> is the ] of the equation.<ref name=Sharaf/> | |||
==Applied mathematics== | |||
===Geometric art and architecture=== | |||
{{Main|Arabesque|Girih tiles|Islamic art|Islamic architecture}} | |||
] artwork in the form of the ] was not widely used in the Middle East or ] until the ] came into full bloom, when Arabesque became a common feature of ]. ] as expounded on by ] (ca. 800–860) in his ''Commentary on Euclid's Elements'', the ] of ] and ] as elaborated on by ] (ca. 780–850), and the development of ]<ref name=Gingerich/> by ] (940–998) and ] by ] (989–1079)<ref name="MacTutor Al-Jayyani"/> for determining the ] and times of ] and ],<ref name=Gingerich/> all served as an impetus for the art form that was to become the Arabesque. | |||
Recent discoveries have shown that geometrical ] patterns were first employed in the ] found in medieval ] dating back over five centuries ago. In 2007, Professor ] of ] and Professor ] of ] published a paper in the journal ''Science'' suggesting that girih tilings possessed properties consistent with ] ] quasicrystalline tilings such as the ]s, predating them by five centuries.<ref name=Lu>{{Citation | |||
| author = Peter J. Lu and Paul J. Steinhardt | |||
| year = 2007 | |||
| title = Decagonal and Quasi-crystalline Tilings in Medieval Islamic Architecture | |||
| journal = ] | |||
| volume = 315 | |||
| pages = 1106–1110 | |||
| url = http://www.physics.harvard.edu/~plu/publications/Science_315_1106_2007.pdf | |||
|format=PDF| doi = 10.1126/science.1135491 | |||
| pmid = 17322056 | |||
| issue = 5815 | |||
| postscript = . | |||
}}</ref><ref></ref> | |||
===Mathematical astronomy=== | |||
{{Main|Islamic astronomy|Zij}} | |||
An impetus behind mathematical ] came from Islamic religious observances, which presented a host of problems in mathematical astronomy, particularly in ]. In solving these religious problems the Islamic scholars went far beyond the Greek mathematical methods.<ref name=Gingerich/> For example, predicting just when the crescent moon would become visible is a special challenge to Islamic mathematical astronomers. Although ]'s theory of the complex lunar motion was tolerably accurate near the time of the new moon, it specified the moon's path only with respect to the ]. To predict the first visibility of the moon, it was necessary to describe its motion with respect to the ], and this problem demands fairly sophisticated ]. Finding the direction of ] and the time of ] are the reasons which led to Muslims developing spherical geometry. Solving any of these problems involves finding the unknown sides or angles of a triangle on the ] from the known sides and angles. A way of finding the time of day, for example, is to construct a triangle whose ] are the ], the north ], and the sun's position. The observer must know the altitude of the sun and that of the pole; the former can be observed, and the latter is equal to the observer's ]. The time is then given by the angle at the intersection of the ] (the ] through the zenith and the pole) and the sun's hour circle (the arc through the sun and the pole).<ref name=Gingerich/><ref name=Tabatabai/> | |||
The '']'' treatises were astronomical books that tabulated the parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. Their principal contributions to mathematical astronomy reflected improved trigonometrical, computational and observational techniques.<ref>Kennedy, ''Islamic Astronomical Tables'', p. 51</ref><ref>Benno van Dalen, PARAMS (Database of parameter values occurring in Islamic astronomical sources), </ref> The ''Zij'' books were extensive, and typically included materials on ], geographical ]s and ]s, ] tables, ], functions in ], the ], planetary motions, computation of ], tables for first visibility of the ], astronomical and/or ] computations, and instructions for astronomical calculations using ] ] models.<ref>Kennedy, ''Islamic Astronomical Tables'', pp. 17–23</ref> Some ''zījes'' go beyond this traditional content to explain or prove the theory or report the observations from which the tables were computed.<ref>Kennedy, ''Islamic Astronomical Tables'', p. 1</ref> | |||
In ], ]'s ''Zij al-Sindh'' (830) contains trigonometric tables for the movements of the sun, the moon and the five planets known at the time.<ref>{{Harv|Dallal|1999|p=163}}</ref> ]'s ''A compendium of the science of stars'' (850) corrected ]'s '']'' and gave revised values for the obliquity of the ], the precessional movement of the ]s of the sun and the moon, and the circumference of the earth.<ref>{{Harv|Dallal|1999|p=164}}</ref> ] (853–929) discovered that the direction of the Sun's ] was changing,<ref>{{Harv|Singer|1959|p=151}} (] {{Harv|Zaimeche|2002}})</ref> and studied the times of the ], lengths for the ] and ], prediction of ]s, and the phenomenon of ].<ref>{{Harv|Wickens|1976|}} (] {{Harv|Zaimeche|2002}})</ref> Around the same time, Yahya Ibn Abi Mansour wrote the ''Al-Zij al-Mumtahan'', in which he completely revised the ''Almagest'' values.<ref>{{citation|title=23rd Annual Conference on the History of Arabic Science|date=October 2001|publisher=], ]}} (] {{Harv|Zaimeche|2002}})</ref> In the 10th century, ] (Azophi) carried out observations on the ]s and described their ]s, ]s, brightness, and ] and drawings for each constellation in his '']'' (964). ] observed more than 10,000 entries for the sun's position for many years using a large ] with a diameter of nearly 1.4 meters. His observations on ]s were still used centuries later in ]'s investigations on the motion of the moon, while his other observations inspired ]'s ''Obliquity of the Ecliptic'' and ''Inequalities of Jupiter and Saturn's''.<ref name=Zaimeche>{{Harv|Zaimeche|2002}}</ref> | |||
In the late 10th century, ] accurately computed the ] to be 23°32'19" (23.53°),<ref>{{Citation|first=Richard P.|last=Aulie|date=March 1994|title=Al-Ghazali Contra Aristotle: An Unforeseen Overture to Science In Eleventh-Century Baghdad|journal=Perspectives on Science and Christian Faith|volume=45|pages=26–46}} (] {{cite web|url=http://www.1001inventions.com/index.cfm?fuseaction=main.viewSection&intSectionID=441|title=References | |||
|publisher=1001 Inventions|accessdate=2008-01-22}})</ref> which was a significant improvement over the Greek and Indian estimates of 23°51'20" (23.86°) and 24°,<ref>{{Harv|Saliba|2007}}</ref> and still very close to the modern measurement of 23°26' (23.44°). In 1006, the ]ian astronomer ] observed ], the brightest ] in recorded history, and left a detailed description of the temporary star. He says that the object was two to three times as large as the disc of ] and about one-quarter the brightness of the ], and that the star was low on the southern horizon. In 1031, ]'s ''Canon Mas’udicus'' introduced the mathematical technique of analysing the ] of the planets, and first states that the motions of the ] and the ] are not identical. Al-Biruni also discovered that the distance between the Earth and the Sun is larger than ]'s estimate, on the basis that Ptolemy disregarded annular eclipses.<ref>{{Citation |last=Saliba |first=George |authorlink=George Saliba |year=1980 |contribution=Al-Biruni |editor-last=Strayer |editor-first=Joseph |title=Dictionary of the Middle Ages |volume=2 |publisher=], New York |page=249}}</ref> | |||
During the "]" of the 13th and 14th centuries, Muslim astronomers realized that astronomy should aim to describe the behavior of ] in mathematical language, and should not remain a mathematical ], which would only save the ]. The Maragha astronomers also realized that the ] view of ] in the universe being only ] or ] was not true, as the ] showed that linear motion could also be produced by applying circular motions only.<ref>{{Harv|Saliba|1994b|pp=245, 250, 256–257}}</ref> Unlike the ancient ] who were not concerned with the coherence between the mathematical and physical principles of a planetary theory, Islamic astronomers insisted on the need to match the mathematics with the real world surrounding them,<ref>{{citation|first=George|last=Saliba|author-link=George Saliba|date=Autumn 1999|title=Seeking the Origins of Modern Science?|journal=BRIIFS|volume=1|issue=2|url=http://www.riifs.org/review_articles/review_v1no2_sliba.htm |accessdate=2008-01-25}}</ref> which gradually evolved from a reality based on ] to one based on an empirical and mathematical ] after the work of ]. The Maragha Revolution was thus characterized by a shift away from the philosophical foundations of ] and ] and towards a greater emphasis on the empirical observation and mathematization of astronomy and of ] in general, as exemplified in the works of Ibn al-Shatir, ], ] and al-Khafri.<ref>{{Harv|Saliba|1994b|pp=42 & 80}}</ref><ref>{{citation|first=Ahmad|last=Dallal|year=2001–2002|title=The Interplay of Science and Theology in the Fourteenth-century Kalam|publisher=From Medieval to Modern in the Islamic World, Sawyer Seminar at the ] |url=http://humanities.uchicago.edu/orgs/institute/sawyer/archive/islam/dallal.html |accessdate=2008-02-02}}</ref><ref>{{Harv|Huff|2003|pp=217–8}}</ref> In particular, Ibn al-Shatir's ] was mathematically identical to the later ].<ref>{{Harv|Saliba|1994b|pp=254 & 256–257}}</ref> | |||
===Mathematical geography and geodesy=== | |||
{{Main|Islamic geography}} | |||
] was a ] who is considered a pioneer in ] and ].]] | |||
The Muslim scholars, who held to the ] theory, used it in an impeccably Islamic manner, to calculate the distance and direction from any given point on the earth to ]. This determined the ], or Muslim direction of prayer. Muslim mathematicians developed ] which was used in these calculations.<ref>David A. King, ''Astronomy in the Service of Islam'', (Aldershot (U.K.): Variorum), 1993.</ref> | |||
Around 830, Caliph ] commissioned a group of astronomers to measure the distance from Tadmur (]) to ], in modern ]. They found the cities to be separated by one degree of latitude and the distance between them to be 66 2/3 miles and thus calculated the Earth's circumference to be 24,000 miles.<ref>''Gharā'ib al-funūn wa-mulah al-`uyūn'' (The Book of Curiosities of the Sciences and Marvels for the Eyes), 2.1 "On the mensuration of the Earth and its division into seven climes, as related by Ptolemy and others," (ff. 22b-23a)</ref> Another estimate given by ] was 56 2/3 Arabic miles per degree, which corresponds to 111.8 km per degree and a circumference of 40,248 km, very close to the currently modern values of 111.3 km per degree and 40,068 km circumference, respectively.<ref>Edward S. Kennedy, ''Mathematical Geography'', pp. 187–188, in {{Harv|Rashed|Morelon|1996|pp=185–201}}</ref> | |||
In mathematical ], ], around 1025, was the first to describe a polar equi-] of the ].<ref>David A. King (1996), "Astronomy and Islamic society: Qibla, gnomics and timekeeping", in Roshdi Rashed, ed., '']'', Vol. 1, pp. 128–184 . ], London and New York.</ref> He was also regarded as the most skilled when it came to mapping ] and measuring the distances between them, which he did for many cities in the Middle East and western ]. He often combined astronomical readings and mathematical equations, in order to develop methods of pin-pointing locations by recording degrees of ] and ]. He also developed similar techniques when it came to measuring the heights of ]s, depths of ]s, and expanse of the ], in ''The Chronology of the Ancient Nations''. He also discussed ] and the ] of the ]. He hypothesized that roughly a quarter of the Earth's surface is habitable by ]s, and also argued that the shores of Asia and Europe were "separated by a vast sea, too dark and dense to navigate and too risky to try" in reference to the Atlantic Ocean and Pacific Ocean.{{Citation needed|date=June 2010}} | |||
] is considered the father of ] for his important contributions to the field,<ref name=Ahmed>Akbar S. Ahmed (1984). "Al-Beruni: The First Anthropologist", ''RAIN'' '''60''', pp. 9–10.</ref><ref>H. Mowlana (2001). "Information in the Arab World", ''Cooperation South Journal'' '''1'''.</ref> along with his significant contributions to geography and geology. At the age of 17, al-Biruni calculated the ] of Kath, ], using the maximum altitude of the Sun. Al-Biruni also solved a complex ] equation in order to accurately compute the ]'s ], which were close to modern values of the Earth's circumference.<ref>James S. Aber (2003). Alberuni calculated the Earth's circumference at a small town of Pind Dadan Khan, District Jhelum, Punjab, Pakistan., ].</ref> His estimate of 6,339.9 km for the ] was only 16.8 km less than the modern value of 6,356.7 km. In contrast to his predecessors who measured the Earth's circumference by sighting the Sun simultaneously from two different locations, al-Biruni developed a new method of using ] calculations based on the angle between a ] and ] top which yielded more accurate measurements of the Earth's circumference and made it possible for it to be measured by a single person from a single location.<ref>Lenn Evan Goodman (1992), ''Avicenna'', p. 31, ], ISBN 041501929X.</ref><ref>{{citation|title=Applicable Problems in History of Mathematics: Practical Examples for the Classroom|author=Behnaz Savizi|journal=Teaching Mathematics and Its Applications|volume=26|issue=1|year=2007|pages=45–50|publisher=]|doi=10.1093/teamat/hrl009}} (] {{cite web|title=Applicable Problems in History of Mathematics; Practical Examples for the Classroom|author=Behnaz Savizi|publisher=]|url=http://people.exeter.ac.uk/PErnest/pome19/Savizi%20-%20Applicable%20Problems.doc|accessdate=2010-02-21}})</ref><ref>{{citation|title=Geometry Activities from Many Cultures|author=Beatrice Lumpkin|publisher=Walch Publishing|year=1997|isbn=0825132851|pages=60 & 112–3}} </ref> | |||
===Mathematical physics=== | |||
{{Main|Islamic physics|Book of Optics}} | |||
]'s work on geometric ], particularly ], in "Book V" of the '']'' (1021) contains the important mathematical problem known as "Alhazen's problem" (''Alhazen'' is the ]ized name of Ibn al-Haytham). It comprises drawing lines from two points in the plane of a circle meeting at a point on the ] and making equal angles with the normal at that point. This leads to an ]. This eventually led Ibn al-Haytham to derive the earliest formula for the sum of the ]s, and using an early ] by ], he developed a method for determining the general formula for the sum of any ] ], which was fundamental to the development of ] and ] ].<ref name=Katz>Victor J. Katz (1995). "Ideas of Calculus in Islam and India", ''Mathematics Magazine'' '''68''' (3), pp. 163–174.</ref> Ibn al-Haytham eventually solved "Alhazen's problem" using ]s and a geometric proof, but Alhazen's problem remained influential in Europe, when later mathematicians such as ], ], ], ], and many others, attempted to find an algebraic solution to the problem, using various methods, including ] and derivation by ]s.<ref name=Smith>John D. Smith (1992). "The Remarkable Ibn al-Haytham", ''The Mathematical Gazette'' '''76''' (475), pp. 189–198.</ref> Mathematicians were not able to find an algebraic solution to the problem until the end of the 20th century.<ref name=Steffens>Bradley Steffens (2006), ''Ibn al-Haytham: First Scientist'', , Morgan Reynolds Publishing, ISBN 1599350246</ref> | |||
Ibn al-Haytham also produced tables of corresponding ] and ] of ] passing from one medium to another show how closely he had approached discovering the ], later attributed to ]. He also correctly accounted for ] being due to ], estimating the Sun's depression to be 19 degrees below the ] during the commencement of the phenomenon in the mornings or at its termination in the evenings.<ref name=Sarton>], ''Introduction to the History of Science'', "The Time of Al-Biruni"</ref> | |||
Ibn al-Haytham systematically endeavoured to mathematize physics in the context of his experimental research and controlled testing, which was oriented by geometric models of the structural mathematical principles that governed physical phenomena, particularly in relation to the explication of the behaviour and nature of vision and light.<ref>{{citation|title=A Philosophical Perspective on Alhazen’s ''Optics''|first=Nader|last=El-Bizri|author-link=Nader El-Bizri|journal=]|volume=15|issue=2|year= 2005|pages=189–218}}</ref> Ibn al-Haytham also advanced in his ''Discourse on Place'' (''Qawl fi al-makan'') a geometrical understanding of place as ''mathematical space'' that is akin to the 17th century conceptions of ''extensio'' by Descartes and ''analysis situs'' by Leibniz. Ibn al-Haytham established his geometrical thesis about ''place as space'' in the context of his mathematical refutation of the Aristotelian physical definition of ''topos'' as a ''boundary surface of a containing body'' (as argued in Book delta of Aristotle's ''Physics'').<ref>{{citation|title=In Defence of the Sovereignty of Philosophy: al-Baghdadi’s Critique of Ibn al-Haytham’s Geometrisation of Place|first=Nader|last=El-Bizri|author-link=Nader El-Bizri|journal=]|volume=17|issue=1|year= 2007|pages=57–80}}</ref> | |||
] (973–1048), and later ] (fl. 1115–1130), were the first to apply ]al ]s to the ] and ] fields of ], particularly for determining ]s, such as those based on the theory of ] and ]. Muslim physicists applied the mathematical theories of ]s and ] techniques, and introduced ]ic and fine ] techniques into the field of statics.<ref name=Rozhanskaya-642>Mariam Rozhanskaya and I. S. Levinova (1996), "Statics", p. 642, in {{Harv|Morelon|Rashed|1996|pp=614–642}}</ref> | |||
Abu 'Abd Allah Muhammad ibn Ma'udh, who lived in ] during the second half of the 11th century, wrote a work on optics later translated into Latin as ''Liber de crepisculis'', which was mistakenly attributed to Alhazen. This was a "short work containing an estimation of the angle of depression of the sun at the beginning of the morning ] and at the end of the evening twilight, and an attempt to calculate on the basis of this and other data the height of the atmospheric moisture responsible for the refraction of the sun's rays." Through his experiments, he obtained the accurate value of 18°, which comes close to the modern value.<ref>{{citation|title=The Authorship of the Liber de crepusculis, an Eleventh-Century Work on Atmospheric Refraction|first=A. I.|last=Sabra|author-link=A. I. Sabra|journal=]|volume=58|issue=1|date=Spring 1967|pages=77–85 |doi=10.1086/350185}}</ref> | |||
In 1574, ] estimated that the ]s are millions of kilometres away from the ] and that the ] is constant, that if light had come from the eye, it would take too long for light "to travel to the star and come back to the eye. But this is not the case, since we see the star as soon as we open our eyes. Therefore the light must emerge from the object not from the eyes."{{Citation needed|date=May 2010}} | |||
==Other fields== | |||
===Cryptography=== | |||
]'s manuscript ''On Deciphering Cryptographic Messages'', containing the first descriptions of ] and ].]] | |||
In the 9th century, ] was a pioneer in ] and ]. He gave the first known recorded explanation of ] in ''A Manuscript on Deciphering Cryptographic Messages''. In particular, he is credited with developing the ] method whereby variations in the frequency of the occurrence of letters could be analyzed and exploited to break ]s (i.e. crypanalysis by frequency analysis).<ref>Simon Singh. The Code Book. pp. 14–20</ref> This was detailed in a text recently rediscovered in the Ottoman archives in Istanbul, ''A Manuscript on Deciphering Cryptographic Messages'', which also covers methods of cryptanalysis, encipherments, cryptanalysis of certain encipherments, and ] analysis of letters and letter combinations in Arabic.{{Citation needed|date=May 2010}} Al-Kindi also had knowledge of ]s centuries before ]. Al-Kindi's book also introduced the classification of ciphers, developed Arabic phonetics and syntax, and described the use of several statistical techniques for cryptoanalysis. This book apparently antedates other cryptology references by several centuries, and it also predates writings on ] and ] by ] and ] by nearly eight centuries.<ref>] (April 1992), "The origins of cryptology: The Arab contributions”, '']'' '''16''' (2): 97–126</ref> | |||
] (1355–1418) wrote the ''Subh al-a 'sha'', a 14-volume encyclopedia which included a section on cryptology. This information was attributed to Taj ad-Din Ali ibn ad-Duraihim ben Muhammad ath-Tha 'alibi al-Mausili who lived from 1312 to 1361, but whose writings on cryptology have been lost. The list of ciphers in this work included both ] and ], and for the first time, a cipher with multiple substitutions for each ] letter. Also traced to Ibn al-Duraihim is an exposition on and worked example of cryptanalysis, including the use of tables of ] and sets of letters which can not occur together in one word. | |||
===Mathematical induction=== | |||
The first known ] by ] was introduced in the ''al-Fakhri'' written by ] around 1000 AD, who used it to prove ] such as the ], ], and the sum formula for ] ].<ref>Victor J. Katz (1998), ''History of Mathematics: An Introduction'', pp. 255–259, ], ISBN 0321016181: | |||
<blockquote>"Another important idea introduced by ] and continued by ] and others was that of an inductive argument for dealing with certain arithmetic sequences. Thus al-Karaji used such an argument to prove the result on the sums of integral cubes already known to ] Al-Karaji did not, however, state a general result for arbitrary ''n''. He stated his theorem for the particular integer 10 His proof, nevertheless, was clearly designed to be extendable to any other integer.</blockquote></ref><ref>{{MacTutor|id=Al-Karaji|title=Abu Bekr ibn Muhammad ibn al-Husayn Al-Karaji}} {{quote|"Al-Karaji also uses a form of mathematical induction in his arguments, although he certainly does not give a rigorous exposition of the principle."}}</ref> His proof was the first to make use of the two basic components of an inductive proof, "namely the ] of the statement for ''n'' = 1 (1 = 1<sup>3</sup>) and the deriving of the truth for ''n'' = ''k'' from that of ''n'' = ''k'' – 1."<ref>Katz (1998), p. 255: <blockquote>"Al-Karaji's argument includes in essence the two basic components of a modern argument by induction, namely the truth of the statement for ''n'' = 1 (1 = 1<sup>3</sup>) and the deriving of the truth for ''n'' = ''k'' from that of ''n'' = ''k'' – 1. Of course, this second component is not explicit since, in some sense, al-Karaji's argument is in reverse; this is, he starts from ''n'' = 10 and goes down to 1 rather than proceeding upward. Nevertheless, his argument in ''al-Fakhri'' is the earliest extant proof of the sum formula for integral cubes."</blockquote></ref> | |||
Shortly afterwards, ] (Alhazen) used the inductive method to prove the sum of ]s, and by extension, the sum of any integral ], which was an important result in ] ]. He only stated it for particular integers, but his proof for those integers was by induction and generalizable.<ref>Victor J. Katz (1995), "Ideas of Calculus in Islam and India", ''Mathematics Magazine'' '''68''' (3), pp. 163–174: | |||
{{quote|"The central idea in ]'s proof of the sum formulas was the derivation of the equation Naturally, he did not state this result in general form. He only stated it for particular integers, but his proof for each of those ''k'' is by induction on ''n'' and is immediately generalizable to any value of ''k''."}}</ref><ref>Katz (1998), pp. 255–259.</ref> | |||
] came closest to a modern proof by mathematical induction in pre-modern times, which he used to extend the proof of the binomial theorem and Pascal's triangle previously given by al-Karaji. Al-Samaw'al's inductive argument was only a short step from the full inductive proof of the general binomial theorem.<ref>Katz (1998), p. 259: <blockquote>"Like the proofs of al-Karaji and ibn al-Haytham, al-Samaw'al's argument contains the two basic components of an inductive proof. He begins with a value for which the result is known, here ''n'' = 2, and then uses the result for a given integer to derive the result for the next. Although al-Samaw'al did not have any way of stating, and therefore proving, the general binomial theorem, to modern readers there is only a short step from al-Samaw'al's argument to a full inductive proof of the binomial theorem."</blockquote></ref> | |||
== Astrolabe == | |||
The ] is a mathematical tool that could be used to solve all the standard problems of spherical astronomy in five different ways. | |||
==See also== | |||
*] | |||
*] | |||
*] | |||
*] | |||
*] | |||
*] | |||
== Notes == | |||
{{Reflist|2}} | |||
== Further reading== | |||
{{Refbegin|2}} | |||
;Bibliographies and biographies | ;Bibliographies and biographies | ||
* ]. ''Geschichte der Arabischen Litteratur''. 1.–2. Band, 1.–3. Supplementband. Berlin: Emil Fischer, 1898, 1902; Leiden: Brill, 1937, 1938, 1942. | * ]. ''Geschichte der Arabischen Litteratur''. 1.–2. Band, 1.–3. Supplementband. Berlin: Emil Fischer, 1898, 1902; Leiden: Brill, 1937, 1938, 1942. | ||
* {{ |
* {{cite book|last=Sánchez Pérez|first=José A.|author-link=José Augusto Sánchez Pérez|title=Biografías de Matemáticos Árabes que florecieron en España|location=Madrid|publisher=Estanislao Maestre|year=1921}} | ||
* {{ |
* {{cite book|last=Sezgin|first=Fuat|author-link=Fuat Sezgin|title=Geschichte Des Arabischen Schrifttums|publisher=Brill Academic Publishers|language=de|year=1997|isbn=90-04-02007-1}} | ||
* {{ |
* {{cite book|last=Suter|first=Heinrich|author-link=Heinrich Suter|title=Die Mathematiker und Astronomen der Araber und ihre Werke|series=Abhandlungen zur Geschichte der Mathematischen Wissenschaften Mit Einschluss Ihrer Anwendungen, X Heft|location=Leipzig|year=1900}} | ||
;Overview | |||
*{{Citation|last=Berggren|first=J. Lennart|authorlink=Len Beggren|title=Episodes in the Mathematics of Medieval Islam|year=1986|publisher=Springer-Verlag|location=New York|isbn=0-387-96318-9}} (Reviewed: {{citation|last=Toomer|first=Gerald J.|title=Episodes in the Mathematics of Medieval Islam|journal=American Mathematical Monthly|volume=95|issue=6|year=1988|url=http://links.jstor.org/sici?sici=0002-9890%28198806%2F07%2995%3A6%3C567%3AEITMOM%3E2.0.CO%3B2-3|doi=10.2307/2322777|pages=567|publisher=Mathematical Association of America|last2=Berggren|first2=J. L.}}; {{citation|first=Jan P.|last=Hogendijk|title=''Episodes in the Mathematics of Medieval Islam'' by J. Lennart Berggren|journal=Journal of the American Oriental Society|volume=109|issue=4|year=1989|pages=697–698|doi=10.2307/604119|url=http://jstor.org/stable/604119|publisher=American Oriental Society|last2=Berggren|first2=J. L.}}) | |||
;Other | |||
*{{Citation | |||
| first=J. Lennart | |||
| last=Berggren | |||
| editor=Victor J. Katz | |||
| title=The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A Sourcebook | |||
| chapter=Mathematics in Medieval Islam | |||
| publisher=Princeton University Press | |||
| year=2007 | |||
| isbn=9780691114859 | |||
}} | |||
*{{Citation | |||
| first=Carl B. | |||
| last=Boyer | |||
| authorlink=Carl Benjamin Boyer | |||
| title=A History of Mathematics | |||
| chapter=The Arabic Hegemony | |||
| edition=Second | |||
| publisher=John Wiley & Sons, Inc | |||
| year=1991 | |||
| isbn=0471543977 | |||
}} | |||
*{{Citation | |||
| first=Roger | |||
| last=Cooke | |||
| authorlink=Roger Cooke | |||
| title=The History of Mathematics: A Brief Course | |||
| chapter=Islamic Mathematics | |||
| publisher=Wiley-Interscience | |||
| year=1997 | |||
| isbn=0471180823 | |||
}} | |||
*{{Citation|last=Daffa'|first=Ali Abdullah al-|authorlink=Ali Abdullah Al-Daffa|title=The Muslim contribution to mathematics|year=1977|publisher=Croom Helm|location=London|isbn=0-85664-464-1}} | |||
* {{Citation|first=Ali Abdullah al-|last=Daffa|first2=J.J.|last2=Stroyls|title=Studies in the exact sciences in medieval Islam|publisher=Wiley|location=New York|year=1984|isbn=0471903205}} | |||
*{{Citation | |||
|last=Eder | |||
|first=Michelle | |||
|year=2000 | |||
|title=Views of Euclid's Parallel Postulate in Ancient Greece and in Medieval Islam | |||
|url=http://www.math.rutgers.edu/~cherlin/History/Papers2000/eder.html | |||
|publisher=] | |||
|accessdate=2008-01-23 | |||
}} | |||
* ]. “The Formation of «Islamic Mathematics»: Sources and Conditions”. ''Filosofi og Videnskabsteori på Roskilde Universitetscenter''. 3. Række: ''Preprints og Reprints'' 1987 Nr. 1. | |||
* {{Citation|last=Joseph|first=George Gheverghese|authorlink=George Gheverghese Joseph|title=The Crest of the Peacock: Non-European Roots of Mathematics|edition=2nd|publisher=Princeton University Press|year=2000|isbn=0691006598}} (Reviewed: {{citation|first=Victor J.|last=Katz|title=''The Crest of the Peacock: Non-European Roots of Mathematics'' by George Gheverghese Joseph|journal=The College Mathematics Journal|volume=23|issue=1|year=1992|pages=82–84|doi=10.2307/2686206|url=http://jstor.org/stable/2686206|publisher=Mathematical Association of America|last2=Joseph|first2=George Gheverghese}}) | |||
*{{Citation | |||
|last=Katz | |||
|first=Victor J. | |||
| authorlink = Victor J. Katz | |||
|year=1998 | |||
|title=History of Mathematics: An Introduction | |||
|publisher=] | |||
|isbn=0321016181 | |||
|oclc=38199387 | |||
}} | |||
* {{Citation|first=E. S.|last=Kennedy|authorlink=Edward Stewart Kennedy|title=Studies in the Islamic Exact Sciences|year=1984|publisher=Syracuse Univ Press|isbn=0815660677}} | |||
* {{MacTutor|class=HistTopics|id=Arabic_mathematics|title=Arabic mathematics: forgotten brilliance?|year=1999}} | |||
* {{Citation|last=Rashed|first=Roshdi|authorlink=Roshdi Rashed|others=Transl. by A. F. W. Armstrong|title=The Development of Arabic Mathematics: Between Arithmetic and Algebra|publisher=Springer|year=2001|isbn=0792325656}} | |||
* {{Citation|last=Rashed|first=Roshdi|others=Transl. by Judith Field with revision of trans. by ]|title=Al-Khwarizmi:The Beginnings of Algebra|publisher=]|year=2009|isbn=0863564305}} | |||
*{{Citation | |||
|last=Rozenfeld | |||
|first=Boris A. | |||
| authorlink = Boris A. Rozenfeld | |||
|year=1988 | |||
|title=A History of Non-Euclidean Geometry: Evolution of the Concept of a Geometric Space | |||
|publisher=] | |||
|isbn=0387964584 | |||
|oclc=15550634 | |||
}} | |||
*{{Citation | |||
|last=Smith | |||
|first=John D. | |||
|year=1992 | |||
|title=The Remarkable Ibn al-Haytham | |||
|journal=The Mathematical Gazette | |||
|volume=76 | |||
|issue=475 | |||
|pages=189–198 | |||
|publisher=] | |||
|doi=10.2307/3620392 | |||
|url=http://jstor.org/stable/3620392 | |||
}} | |||
* {{Citation|first=Adolf P.|last=Youschkevitch|authorlink=Adolph Pavlovich Yushkevich|coauthors=Boris A. Rozenfeld|title=Die Mathematik der Länder des Ostens im Mittelalter|year=1960|location=Berlin}} Sowjetische Beiträge zur Geschichte der Naturwissenschaft pp. 62–160. | |||
* {{Citation|first=Adolf P.|last=Youschkevitch|title=Les mathématiques arabes: VIII<sup>e</sup>-XV<sup>e</sup> siècles|others=translated by M. Cazenave and K. Jaouiche|publisher=Vrin|location=Paris|year=1976|isbn=978-2-7116-0734-1}} | |||
{{Refend}} | |||
; Television documentaries | |||
== External links == | |||
* ] (presenter) (2008). "The Genius of the East". '']''. ]. | |||
{{Refbegin}} | |||
* ] (presenter) (2010). '']''. ]. | |||
* by De Lacy O'Leary | |||
* Hogendijk, Jan P. (January 1999). . | |||
{{Refend}} | {{Refend}} | ||
==External links== | |||
{{Commonscat|Mathematics of the Islamic Golden Age}} | |||
*{{cite web|last=Hogendijk|first=Jan P.|author-link=Jan Hogendijk|date=January 1999|url=http://www.jphogendijk.nl/publ/Islamath.html|title=Bibliography of Mathematics in Medieval Islamic Civilization}} | |||
*{{MacTutor|class=HistTopics|id=Arabic_mathematics|title=Arabic mathematics: forgotten brilliance?|year=1999}} | |||
* | |||
* | |||
{{History of mathematics}} | |||
{{Islamic mathematics}} | {{Islamic mathematics}} | ||
{{Islamic studies}} | |||
{{DEFAULTSORT:Mathematics In Medieval Islam}} | {{DEFAULTSORT:Mathematics In Medieval Islam}} | ||
] | ] | ||
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Latest revision as of 22:03, 7 January 2025
Mathematics during the Golden Age of Islam, especially during the 9th and 10th centuries, was built upon syntheses of Greek mathematics (Euclid, Archimedes, Apollonius) and Indian mathematics (Aryabhata, Brahmagupta). Important developments of the period include extension of the place-value system to include decimal fractions, the systematised study of algebra and advances in geometry and trigonometry.
The medieval Islamic world underwent significant developments in mathematics. Muhammad ibn Musa al-Khwārizmī played a key role in this transformation, introducing algebra as a distinct field in the 9th century. Al-Khwārizmī's approach, departing from earlier arithmetical traditions, laid the groundwork for the arithmetization of algebra, influencing mathematical thought for an extended period. Successors like Al-Karaji expanded on his work, contributing to advancements in various mathematical domains. The practicality and broad applicability of these mathematical methods facilitated the dissemination of Arabic mathematics to the West, contributing substantially to the evolution of Western mathematics.
Arabic mathematical knowledge spread through various channels during the medieval era, driven by the practical applications of Al-Khwārizmī's methods. This dissemination was influenced not only by economic and political factors but also by cultural exchanges, exemplified by events such as the Crusades and the translation movement. The Islamic Golden Age, spanning from the 8th to the 14th century, marked a period of considerable advancements in various scientific disciplines, attracting scholars from medieval Europe seeking access to this knowledge. Trade routes and cultural interactions played a crucial role in introducing Arabic mathematical ideas to the West. The translation of Arabic mathematical texts, along with Greek and Roman works, during the 14th to 17th century, played a pivotal role in shaping the intellectual landscape of the Renaissance.
Origin and spread of Arab-Islamic mathematics
Arabic mathematics, particularly algebra, developed significantly during the medieval period. Muhammad ibn Musa al-Khwārizmī's (Arabic: محمد بن موسى الخوارزمي; c. 780 – c. 850) work between AD 813 and 833 in Baghdad was a turning point. He introduced the term "algebra" in the title of his book, "Kitab al-jabr wa al-muqabala," marking it as a distinct discipline. He regarded his work as "a short work on Calculation by (the rules of) Completion and Reduction, confining it to what is easiest and most useful in arithmetic". Later, people commented his work was not just a theoretical treatise but also practical, aimed at solving problems in areas like commerce and land measurement.
Al-Khwārizmī's approach was groundbreaking in that it did not arise from any previous "arithmetical" tradition, including that of Diophantus. He developed a new vocabulary for algebra, distinguishing between purely algebraic terms and those shared with arithmetic. Al-Khwārizmī noticed that the representation of numbers is crucial in daily life. Thus, he wanted to find or summarize a way to simplify the mathematical operation, so-called later, the algebra. His algebra was initially focused on linear and quadratic equations and the elementary arithmetic of binomials and trinomials. This approach, which involved solving equations using radicals and related algebraic calculations, influenced mathematical thinking long after his death.
Al-Khwārizmī's proof of the rule for solving quadratic equations of the form (ax^2 + bx = c), commonly referred to as "squares plus roots equal numbers," was a monumental achievement in the history of algebra. This breakthrough laid the groundwork for the systematic approach to solving quadratic equations, which became a fundamental aspect of algebra as it developed in the Western world. Al-Khwārizmī's method, which involved completing the square, not only provided a practical solution for equations of this type but also introduced an abstract and generalized approach to mathematical problems. His work, encapsulated in his seminal text "Al-Kitab al-Mukhtasar fi Hisab al-Jabr wal-Muqabala" (The Compendious Book on Calculation by Completion and Balancing), was translated into Latin in the 12th century. This translation played a pivotal role in the transmission of algebraic knowledge to Europe, significantly influencing mathematicians during the Renaissance and shaping the evolution of modern mathematics. Al-Khwārizmī's contributions, especially his proof for quadratic equations, are a testament to the rich mathematical heritage of the Islamic world and its enduring impact on Western mathematics.
The spread of Arabic mathematics to the West was facilitated by several factors. The practicality and general applicability of al-Khwārizmī's methods were significant. They were designed to convert numerical or geometrical problems into equations in normal form, leading to canonical solution formulae. His work and that of his successors like al-Karaji laid the foundation for advances in various mathematical fields, including number theory, numerical analysis, and rational Diophantine analysis.
Al-Khwārizmī's algebra was an autonomous discipline with its historical perspective, eventually leading to the "arithmetization of algebra". His successors expanded on his work, adapting it to new theoretical and technical challenges and reorienting it towards a more arithmetical direction for abstract algebraic calculation.
Arabic mathematics, epitomized by al-Khwārizmī's work, was crucial in shaping the mathematical landscape. Its spread to the West was driven by its practical applications, the expansion of mathematical concepts by his successors, and the translation and adaptation of these ideas into the Western context. This spread was a complex process involving economics, politics, and cultural exchange, greatly influencing Western mathematics.
The period known as the Islamic Golden Age (8th to 14th century) was characterized by significant advancements in various fields, including mathematics. Scholars in the Islamic world made substantial contributions to mathematics, astronomy, medicine, and other sciences. As a result, the intellectual achievements of Islamic scholars attracted the attention of scholars in medieval Europe who sought to access this wealth of knowledge. Trade routes, such as the Silk Road, facilitated the movement of goods, ideas, and knowledge between the East and West. Cities like Baghdad, Cairo, and Cordoba became centers of learning and attracted scholars from different cultural backgrounds. Therefore, mathematical knowledge from the Islamic world found its way to Europe through various channels. Meanwhile, the Crusades connected Western Europeans with the Islamic world. While the primary purpose of the Crusades was military, there was also cultural exchange and exposure to Islamic knowledge, including mathematics. European scholars who traveled to the Holy Land and other parts of the Islamic world gained access to Arabic manuscripts and mathematical treatises. During the 14th to 17th century, the translation of Arabic mathematical texts, along with Greek and Roman ones, played a crucial role in shaping the intellectual landscape of the Renaissance. Figures like Fibonacci, who studied in North Africa and the Middle East, helped introduce and popularize Arabic numerals and mathematical concepts in Europe.
Concepts
Algebra
Further information: History of algebraThe study of algebra, the name of which is derived from the Arabic word meaning completion or "reunion of broken parts", flourished during the Islamic golden age. Muhammad ibn Musa al-Khwarizmi, a Persian scholar in the House of Wisdom in Baghdad was the founder of algebra, is along with the Greek mathematician Diophantus, known as the father of algebra. In his book The Compendious Book on Calculation by Completion and Balancing, Al-Khwarizmi deals with ways to solve for the positive roots of first and second-degree (linear and quadratic) polynomial equations. He introduces the method of reduction, and unlike Diophantus, also gives general solutions for the equations he deals with.
Al-Khwarizmi's algebra was rhetorical, which means that the equations were written out in full sentences. This was unlike the algebraic work of Diophantus, which was syncopated, meaning that some symbolism is used. The transition to symbolic algebra, where only symbols are used, can be seen in the work of Ibn al-Banna' al-Marrakushi and Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī.
On the work done by Al-Khwarizmi, J. J. O'Connor and Edmund F. Robertson said:
"Perhaps one of the most significant advances made by Arabic mathematics began at this time with the work of al-Khwarizmi, namely the beginnings of algebra. It is important to understand just how significant this new idea was. It was a revolutionary move away from the Greek concept of mathematics which was essentially geometry. Algebra was a unifying theory which allowed rational numbers, irrational numbers, geometrical magnitudes, etc., to all be treated as "algebraic objects". It gave mathematics a whole new development path so much broader in concept to that which had existed before, and provided a vehicle for the future development of the subject. Another important aspect of the introduction of algebraic ideas was that it allowed mathematics to be applied to itself in a way which had not happened before."
— MacTutor History of Mathematics archive
Several other mathematicians during this time period expanded on the algebra of Al-Khwarizmi. Abu Kamil Shuja' wrote a book of algebra accompanied with geometrical illustrations and proofs. He also enumerated all the possible solutions to some of his problems. Abu al-Jud, Omar Khayyam, along with Sharaf al-Dīn al-Tūsī, found several solutions of the cubic equation. Omar Khayyam found the general geometric solution of a cubic equation.
Cubic equations
Further information: Cubic equationOmar Khayyam (c. 1038/48 in Iran – 1123/24) wrote the Treatise on Demonstration of Problems of Algebra containing the systematic solution of cubic or third-order equations, going beyond the Algebra of al-Khwārizmī. Khayyám obtained the solutions of these equations by finding the intersection points of two conic sections. This method had been used by the Greeks, but they did not generalize the method to cover all equations with positive roots.
Sharaf al-Dīn al-Ṭūsī (? in Tus, Iran – 1213/4) developed a novel approach to the investigation of cubic equations—an approach which entailed finding the point at which a cubic polynomial obtains its maximum value. For example, to solve the equation , with a and b positive, he would note that the maximum point of the curve occurs at , and that the equation would have no solutions, one solution or two solutions, depending on whether the height of the curve at that point was less than, equal to, or greater than a. His surviving works give no indication of how he discovered his formulae for the maxima of these curves. Various conjectures have been proposed to account for his discovery of them.
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Induction
See also: Mathematical induction § HistoryThe earliest implicit traces of mathematical induction can be found in Euclid's proof that the number of primes is infinite (c. 300 BCE). The first explicit formulation of the principle of induction was given by Pascal in his Traité du triangle arithmétique (1665).
In between, implicit proof by induction for arithmetic sequences was introduced by al-Karaji (c. 1000) and continued by al-Samaw'al, who used it for special cases of the binomial theorem and properties of Pascal's triangle.
Irrational numbers
The Greeks had discovered irrational numbers, but were not happy with them and only able to cope by drawing a distinction between magnitude and number. In the Greek view, magnitudes varied continuously and could be used for entities such as line segments, whereas numbers were discrete. Hence, irrationals could only be handled geometrically; and indeed Greek mathematics was mainly geometrical. Islamic mathematicians including Abū Kāmil Shujāʿ ibn Aslam and Ibn Tahir al-Baghdadi slowly removed the distinction between magnitude and number, allowing irrational quantities to appear as coefficients in equations and to be solutions of algebraic equations. They worked freely with irrationals as mathematical objects, but they did not examine closely their nature.
In the twelfth century, Latin translations of Al-Khwarizmi's Arithmetic on the Indian numerals introduced the decimal positional number system to the Western world. His Compendious Book on Calculation by Completion and Balancing presented the first systematic solution of linear and quadratic equations. In Renaissance Europe, he was considered the original inventor of algebra, although it is now known that his work is based on older Indian or Greek sources. He revised Ptolemy's Geography and wrote on astronomy and astrology. However, C.A. Nallino suggests that al-Khwarizmi's original work was not based on Ptolemy but on a derivative world map, presumably in Syriac or Arabic.
Spherical trigonometry
Further information: Law of sines and History of trigonometryThe spherical law of sines was discovered in the 10th century: it has been attributed variously to Abu-Mahmud Khojandi, Nasir al-Din al-Tusi and Abu Nasr Mansur, with Abu al-Wafa' Buzjani as a contributor. Ibn Muʿādh al-Jayyānī's The book of unknown arcs of a sphere in the 11th century introduced the general law of sines. The plane law of sines was described in the 13th century by Nasīr al-Dīn al-Tūsī. In his On the Sector Figure, he stated the law of sines for plane and spherical triangles and provided proofs for this law.
Negative numbers
Further information: Negative numbersIn the 9th century, Islamic mathematicians were familiar with negative numbers from the works of Indian mathematicians, but the recognition and use of negative numbers during this period remained timid. Al-Khwarizmi did not use negative numbers or negative coefficients. But within fifty years, Abu Kamil illustrated the rules of signs for expanding the multiplication . Al-Karaji wrote in his book al-Fakhrī that "negative quantities must be counted as terms". In the 10th century, Abū al-Wafā' al-Būzjānī considered debts as negative numbers in A Book on What Is Necessary from the Science of Arithmetic for Scribes and Businessmen.
By the 12th century, al-Karaji's successors were to state the general rules of signs and use them to solve polynomial divisions. As al-Samaw'al writes:
the product of a negative number—al-nāqiṣ—by a positive number—al-zāʾid—is negative, and by a negative number is positive. If we subtract a negative number from a higher negative number, the remainder is their negative difference. The difference remains positive if we subtract a negative number from a lower negative number. If we subtract a negative number from a positive number, the remainder is their positive sum. If we subtract a positive number from an empty power (martaba khāliyya), the remainder is the same negative, and if we subtract a negative number from an empty power, the remainder is the same positive number.
Double false position
Further information: False position methodBetween the 9th and 10th centuries, the Egyptian mathematician Abu Kamil wrote a now-lost treatise on the use of double false position, known as the Book of the Two Errors (Kitāb al-khaṭāʾayn). The oldest surviving writing on double false position from the Middle East is that of Qusta ibn Luqa (10th century), an Arab mathematician from Baalbek, Lebanon. He justified the technique by a formal, Euclidean-style geometric proof. Within the tradition of Golden Age Muslim mathematics, double false position was known as hisāb al-khaṭāʾayn ("reckoning by two errors"). It was used for centuries to solve practical problems such as commercial and juridical questions (estate partitions according to rules of Quranic inheritance), as well as purely recreational problems. The algorithm was often memorized with the aid of mnemonics, such as a verse attributed to Ibn al-Yasamin and balance-scale diagrams explained by al-Hassar and Ibn al-Banna, who were each mathematicians of Moroccan origin.
Influences
The influence of medieval Arab-Islamic mathematics to the rest of the world is wide and profound, in both the realm of science and mathematics. The knowledge of the Arabs went into the western world through Spain and Sicily during the translation movement. "The Moors (western Mohammedans from that part of North Africa once known as Mauritania) crossed over into Spain early in the seventh century, bringing with them the cultural resources of the Arab world". In the 13th century, King Alfonso X of Castile established the Toledo School of Translators, in the Kingdom of Castile, where scholars translated numerous scientific and philosophical works from Arabic into Latin. The translations included Islamic contributions to trigonometry, which helps European mathematicians and astronomers in their studies. European scholars such as Gerard of Cremona (1114–1187) played a key role in translating and disseminating these works, thus making them accessible to a wider audience. Cremona is said to have translated into Latin "no fewer than 90 complete Arabic texts." European mathematicians, building on the foundations laid by Islamic scholars, further developed practical trigonometry for applications in navigation, cartography, and celestial navigation, thus pushing forward the age of discovery and scientific revolution. The practical applications of trigonometry for navigation and astronomy became increasingly important during the Age of Exploration.
Al-Battānī is one of the islamic mathematicians who made great contributions to the development of trigonometry. He "innovated new trigonometric functions, created a table of cotangents, and made some formulas in spherical trigonometry." These discoveries, together with his astronomical works which are praised for their accuracy, greatly advanced astronomical calculations and instruments.
Al-Khayyām (1048–1131) was a Persian mathematician, astronomer, and poet, known for his work on algebra and geometry, particularly his investigations into the solutions of cubic equations. He was "the first in history to elaborate a geometrical theory of equations with degrees ≤ 3", and has great influence on the work of Descartes, a French mathematician who is often regarded as the founder of analytical geometry. Indeed, "to read Descartes' Géométrie is to look upstream towards al-Khayyām and al-Ṭūsī; and downstream towards Newton, Leibniz, Cramer, Bézout and the Bernoulli brothers". Numerous problems that appear in "La Géométrie" (Geometry) have foundations that date back to al-Khayyām.
Abū Kāmil (Arabic: أبو كامل شجاع بن أسلم بن محمد بن شجاع, also known as Al-ḥāsib al-miṣrī—lit. "The Egyptian Calculator") (c. 850 – c. 930), was studied algebra following the author of Algebra, al-Khwārizmī. His Book of Algebra (Kitāb fī al-jabr wa al-muqābala) is "essentially a commentary on and elaboration of al-Khwārizmī's work; in part for that reason and in part for its own merit, the book enjoyed widespread popularity in the Muslim world". It contains 69 problems, which is more than al-Khwārizmī who had 40 in his book. Abū Kāmil's Algebra plays a significant role in shaping the trajectory of Western mathematics, particularly in its impact on the works of the Italian mathematician Leonardo of Pisa, widely recognized as Fibonacci. In his Liber Abaci (1202), Fibonacci extensively incorporated ideas from Arabic mathematicians, using approximately 29 problems from Book of Algebra with scarce modification.
Western historians' perception of the contribution of Arab mathematicians
Despite the fundamental works Arabic mathematicians have done on the development of Algebra and algebraic geometry, Western historians in the 18th and early 19th century still regarded it as a fact that Classical science and math were unique phenomena of the West. Even though some math contributions from Arab mathematicians are occasionally acknowledged, they are considered to be "outside history or only integrated in so far as it contributed to science, which is essentially European", and just some technical innovations to the Greek heritage rather than open up a completely new branch of mathematics. In the French philosopher Ernest Renan's work, Arabic math is merely "a reflection of Greece, combined with Persian and Indian influences". And according to Duhem, "Arabic science only reproduced the teachings received from Greek science". Besides being considered as merely some insignificant additions or reflections to the great tradition of Greek classical science, math works from Arabic mathematicians are also blamed for lacking rigor and too focused on practical applications and calculations, and this is why Western historians argued they could never reach the level of Greek mathematicians. As Tannery wrote, Arabic math "in no way superseded the level attained by Diophantus". On the other hand, they perceived that Western mathematicians went into a very different way both in its method employed and ultimate purpose, "the hallmark of Western science in its Greek origins as well as in its modern renaissance, is its conformity to rigorous standards". Thus, the perceived non-rigorous proof in Arabic mathematicians' book authorizes Bourbaki to exclude the Arabic period when he retraced the evolution of algebra. And instead, the history of classical algebra is written as the work of the Renaissance and the origin of algebraic geometry is traced back to Descartes, while Arabic mathematicians' contributions are ignored deliberately. In Rashed's words: "To justify the exclusion of science written in Arabic from the history of science, one invokes its absence of rigor, its calculatory appearance and its practical aims. Furthermore, strictly dependent on Greek science and, lastly, incapable of introducing experimental norms, scientists of that time were relegated to the role of conscientious guardians of the Hellenistic museum."
In 18th century Germany and France, the prevailing Orientalist view was "East and West oppose each other not as geographical but as historical positivities", which labeled "Rationalism" as the essence of the West, while the "Call of the Orient" movement emerged in the 19th century was interpreted as "against Rationalism" and a return to a more "spiritual and harmonious" lifestyle. Thus, the prevailing Orientalism in that period was one of the main reasons why Arabic mathematicians were often ignored for their contributions, as people outside the West were considered to be lacking the necessary rationality and scientific spirit to made significant contributions to math and science.
Conclusion
The medieval Arab-Islamic world played a crucial role in shaping the trajectory of mathematics, with al-Khwārizmī's algebraic innovations serving as a cornerstone. The dissemination of Arabic mathematics to the West during the Islamic Golden Age, facilitated by cultural exchanges and translations, left a lasting impact on Western mathematical thought. Mathematicians like Al-Battānī, Al-Khayyām, and Abū Kāmil, with their contributions to trigonometry, algebra, and geometry, extended their influence beyond their time. Despite the foundational contributions of Arab mathematicians, Western historians in the 18th and early 19th centuries, influenced by Orientalist views, sometimes marginalized these achievements. The East lacking rationality and scientific spirit perpetuated a biased perspective, hindering the recognition of the significant role played by Arabic mathematics in the development of algebra and other mathematical disciplines. Reevaluating the history of mathematics necessitates acknowledging the interconnectedness of diverse mathematical traditions and dispelling the notion of a uniquely European mathematical heritage. The contributions of Arab mathematicians, marked by practical applications and theoretical innovations, form an integral part of the rich tapestry of mathematical history, and deserves recognition.
Other major figures
- 'Abd al-Hamīd ibn Turk (fl. 830) (quadratics)
- Sind ibn Ali (d. after 864)
- Thabit ibn Qurra (826–901)
- Al-Battānī (before 858 – 929)
- Abū Kāmil (c. 850 – c. 930)
- Abu'l-Hasan al-Uqlidisi (fl. 952) (arithmetic)
- 'Abd al-'Aziz al-Qabisi (d. 967)
- Abū Sahl al-Qūhī (c. 940–1000) (centres of gravity)
- Ibn al-Haytham (c. 965–1040)
- Abū al-Rayḥān al-Bīrūnī (973–1048) (trigonometry)
- Al-Khayyām (1048–1131)
- Ibn Maḍāʾ (c. 1116–1196)
- Ismail al-Jazari (1136–1206)
- Jamshīd al-Kāshī (c. 1380–1429) (decimals and estimation of the circle constant)
Gallery
- Engraving of Abū Sahl al-Qūhī's perfect compass to draw conic sections
- The theorem of Ibn Haytham
See also
- Arabic numerals
- Indian influence on Islamic mathematics in medieval Islam
- History of calculus
- History of geometry
- Science in the medieval Islamic world
- Timeline of science and engineering in the Muslim world
References
- Katz (1993): "A complete history of mathematics of medieval Islam cannot yet be written, since so many of these Arabic manuscripts lie unstudied... Still, the general outline... is known. In particular, Islamic mathematicians fully developed the decimal place-value number system to include decimal fractions, systematised the study of algebra and began to consider the relationship between algebra and geometry, studied and made advances on the major Greek geometrical treatises of Euclid, Archimedes, and Apollonius, and made significant improvements in plane and spherical geometry."
^ Smith (1958), Vol. 1, Chapter VII.4: "In a general way it may be said that the Golden Age of Arabian mathematics was confined largely to the 9th and 10th centuries; that the world owes a great debt to Arab scholars for preserving and transmitting to posterity the classics of Greek mathematics; and that their work was chiefly that of transmission, although they developed considerable originality in algebra and showed some genius in their work in trigonometry." - Lumpkin, Beatrice; Zitler, Siham (1992). "Cairo: Science Academy of the Middle Ages". In Van Sertima, Ivan (ed.). Golden age of the Moor, Volume 11. Transaction Publishers. p. 394. ISBN 1-56000-581-5. "The Islamic mathematicians exercised a prolific influence on the development of science in Europe, enriched as much by their own discoveries as those they had inherited by the Greeks, the Indians, the Syrians, the Babylonians, etc."
- ^ ben Musa, Mohammed (2013-03-28). The Algebra of Mohammed ben Musa. Cambridge University Press. ISBN 978-1-108-05507-9.
- ^ Swetz, Frank J. (2012-08-15). Mathematical Treasures: Mesopotamian Accounting Tokens (Report). Washington, DC: The MAA Mathematical Sciences Digital Library.
- "Extending al-Karaji's Work on Sums of Odd Powers of Integers - Introduction | Mathematical Association of America". maa.org. Retrieved 2023-12-15.
- "algebra". Online Etymology Dictionary.
- Boyer 1991, p. 228.
- Swetz, Frank J. (1993). Learning Activities from the History of Mathematics. Walch Publishing. p. 26. ISBN 978-0-8251-2264-4.
- ^ Gullberg, Jan (1997). Mathematics: From the Birth of Numbers. W. W. Norton. p. 298. ISBN 0-393-04002-X.
- O'Connor, John J.; Robertson, Edmund F., "al-Marrakushi ibn Al-Banna", MacTutor History of Mathematics Archive, University of St Andrews
- O'Connor, John J.; Robertson, Edmund F., "Arabic mathematics: forgotten brilliance?", MacTutor History of Mathematics Archive, University of St Andrews
- Struik 1987, p. 96.
- ^ Boyer 1991, pp. 241–242.
- Struik 1987, p. 97.
- Berggren, J. Lennart; Al-Tūsī, Sharaf Al-Dīn; Rashed, Roshdi (1990). "Innovation and Tradition in Sharaf al-Dīn al-Ṭūsī's al-Muʿādalāt". Journal of the American Oriental Society. 110 (2): 304–309. doi:10.2307/604533. JSTOR 604533.
- ^ Sesiano, Jacques (2000). "Islamic Mathematics". In Selin, Helaine (ed.). Mathematics Across Cultures: The History of Non-Western Mathematics. Springer Netherlands. pp. 137–165. doi:10.1007/978-94-011-4301-1_9. ISBN 978-94-011-4301-1.
- O'Connor, John J.; Robertson, Edmund F., "Abu Mansur ibn Tahir Al-Baghdadi", MacTutor History of Mathematics Archive, University of St Andrews
- Allen, G. Donald (n.d.). "The History of Infinity" (PDF). Texas A&M University. Retrieved 7 September 2016.
- Struik 1987, p. 93
- Rosen 1831, p. v–vi.
- Toomer, Gerald (1990). "Al-Khwārizmī, Abu Ja'far Muḥammad ibn Mūsā". In Gillispie, Charles Coulston (ed.). Dictionary of Scientific Biography. Vol. 7. New York: Charles Scribner's Sons. ISBN 0-684-16962-2 – via Encyclopedia.com.
- Nallino 1939.
- O'Connor, John J.; Robertson, Edmund F., "Abu Abd Allah Muhammad ibn Muadh Al-Jayyani", MacTutor History of Mathematics Archive, University of St Andrews
- Berggren 2007, p. 518.
- ^ Rashed, R. (1994-06-30). The Development of Arabic Mathematics: Between Arithmetic and Algebra. Springer. pp. 36–37. ISBN 9780792325659.
- ^ Mat Rofa Bin Ismail (2008), "Algebra in Islamic Mathematics", in Helaine Selin (ed.), Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures, vol. 1 (2nd ed.), Springer, p. 115, ISBN 9781402045592
- Schwartz, R. K. (2004). Issues in the Origin and Development of Hisab al-Khata'ayn (Calculation by Double False Position) (PDF). Eighth North African Meeting on the History of Arab Mathematics. Radès, Tunisia. Archived from the original (PDF) on 2014-05-16. Retrieved 2012-06-08. "Issues in the Origin and Development of Hisab al-Khata'ayn (Calculation by Double False Position)". Archived from the original (.doc) on 2011-09-15.
- ^ Masters, Barry R. (2011-06-08). "Biomedical ethics, 7th edition David DeGrazia, Thomas A. Mappes, Jeffrey Brand-Ballard: 2010, Softcover, 732pp, ISBN-9780073407456 £171.15 McGraw-Hill Incorporated". Graefe's Archive for Clinical and Experimental Ophthalmology. 250 (1): 159–160. doi:10.1007/s00417-011-1640-x. ISSN 0721-832X.
- "Edited by", Contributions to Non-Standard Analysis, Elsevier, pp. iii, 1972, retrieved 2023-12-15
- ^ Rashed, Roshdi (2014-08-21). Classical Mathematics from Al-Khwarizmi to Descartes. Routledge. ISBN 978-1-317-62239-0.
- ^ Masters, Barry R. (2011-06-08). "Biomedical ethics, 7th edition David DeGrazia, Thomas A. Mappes, Jeffrey Brand-Ballard: 2010, Softcover, 732pp, ISBN-9780073407456 £171.15 McGraw-Hill Incorporated". Graefe's Archive for Clinical and Experimental Ophthalmology. 250 (1): 159–160. doi:10.1007/s00417-011-1640-x. ISSN 0721-832X.
- ^ Rashed, Roshdi (1994). "The Development of Arabic Mathematics: Between Arithmetic and Algebra". Boston Studies in the Philosophy of Science. doi:10.1007/978-94-017-3274-1. ISSN 0068-0346.
Sources
- Berggren, J. Lennart (2007). "Mathematics in Medieval Islam". In Victor J. Katz (ed.). The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A Sourcebook (2nd ed.). Princeton, New Jersey: Princeton University Press. ISBN 978-0-691-11485-9.
- Boyer, Carl B. (1991), "Greek Trigonometry and Mensuration, and The Arabic Hegemony", A History of Mathematics (2nd ed.), New York City: John Wiley & Sons, ISBN 0-471-54397-7
- Katz, Victor J. (1993). A History of Mathematics: An Introduction. HarperCollins college publishers. ISBN 0-673-38039-4.
- Nallino, C.A. (1939), "Al-Ḥuwārismī e il suo rifacimento della Geografia di Tolomeo", Raccolta di scritti editi e inediti (in Italian), vol. V, Rome: Istituto per l'Oriente, pp. 458–532
- Rosen, Fredrick (1831). The Algebra of Mohammed Ben Musa. Kessinger Publishing. ISBN 1-4179-4914-7.
- Smith, David E. (1958). History of Mathematics. Dover Publications. ISBN 0-486-20429-4.
- Struik, Dirk J. (1987), A Concise History of Mathematics (4th rev. ed.), Dover Publications, ISBN 0-486-60255-9
Further reading
- Books on Islamic mathematics
- Berggren, J. Lennart (1986). Episodes in the Mathematics of Medieval Islam. New York: Springer-Verlag. ISBN 0-387-96318-9.
- Review: Toomer, Gerald J.; Berggren, J. L. (1988). "Episodes in the Mathematics of Medieval Islam". American Mathematical Monthly. 95 (6). Mathematical Association of America: 567. doi:10.2307/2322777. JSTOR 2322777.
- Review: Hogendijk, Jan P.; Berggren, J. L. (1989). "Episodes in the Mathematics of Medieval Islam by J. Lennart Berggren". Journal of the American Oriental Society. 109 (4). American Oriental Society: 697–698. doi:10.2307/604119. JSTOR 604119.
- Daffa', Ali Abdullah al- (1977). The Muslim contribution to mathematics. London: Croom Helm. ISBN 0-85664-464-1.
- Ronan, Colin A. (1983). The Cambridge Illustrated History of the World's Science. Cambridge University Press. ISBN 0-521-25844-8.
- Rashed, Roshdi (2001). The Development of Arabic Mathematics: Between Arithmetic and Algebra. Translated by A. F. W. Armstrong. Springer. ISBN 0-7923-2565-6.
- Youschkevitch, Adolf P.; Rozenfeld, Boris A. (1960). Die Mathematik der Länder des Ostens im Mittelalter. Berlin.
{{cite book}}
: CS1 maint: location missing publisher (link) Sowjetische Beiträge zur Geschichte der Naturwissenschaft pp. 62–160. - Youschkevitch, Adolf P. (1976). Les mathématiques arabes: VIII–XV siècles. translated by M. Cazenave and K. Jaouiche. Paris: Vrin. ISBN 978-2-7116-0734-1.
- Book chapters on Islamic mathematics
- Lindberg, D.C., and M. H. Shank, eds. The Cambridge History of Science. Volume 2: Medieval Science (Cambridge UP, 2013), chapters 2 and 3 mathematics in Islam.
- Cooke, Roger (1997). "Islamic Mathematics". The History of Mathematics: A Brief Course. Wiley-Interscience. ISBN 0-471-18082-3.
- Books on Islamic science
- Daffa, Ali Abdullah al-; Stroyls, J.J. (1984). Studies in the exact sciences in medieval Islam. New York: Wiley. ISBN 0-471-90320-5.
- Kennedy, E. S. (1984). Studies in the Islamic Exact Sciences. Syracuse Univ Press. ISBN 0-8156-6067-7.
- Books on the history of mathematics
- Joseph, George Gheverghese (2000). The Crest of the Peacock: Non-European Roots of Mathematics (2nd ed.). Princeton University Press. ISBN 0-691-00659-8. (Reviewed: Katz, Victor J.; Joseph, George Gheverghese (1992). "The Crest of the Peacock: Non-European Roots of Mathematics by George Gheverghese Joseph". The College Mathematics Journal. 23 (1). Mathematical Association of America: 82–84. doi:10.2307/2686206. JSTOR 2686206.)
- Youschkevitch, Adolf P. (1964). Gesichte der Mathematik im Mittelalter. Leipzig: BG Teubner Verlagsgesellschaft.
- Journal articles on Islamic mathematics
- Høyrup, Jens. “The Formation of «Islamic Mathematics»: Sources and Conditions”. Filosofi og Videnskabsteori på Roskilde Universitetscenter. 3. Række: Preprints og Reprints 1987 Nr. 1.
- Bibliographies and biographies
- Brockelmann, Carl. Geschichte der Arabischen Litteratur. 1.–2. Band, 1.–3. Supplementband. Berlin: Emil Fischer, 1898, 1902; Leiden: Brill, 1937, 1938, 1942.
- Sánchez Pérez, José A. (1921). Biografías de Matemáticos Árabes que florecieron en España. Madrid: Estanislao Maestre.
- Sezgin, Fuat (1997). Geschichte Des Arabischen Schrifttums (in German). Brill Academic Publishers. ISBN 90-04-02007-1.
- Suter, Heinrich (1900). Die Mathematiker und Astronomen der Araber und ihre Werke. Abhandlungen zur Geschichte der Mathematischen Wissenschaften Mit Einschluss Ihrer Anwendungen, X Heft. Leipzig.
{{cite book}}
: CS1 maint: location missing publisher (link)
- Television documentaries
- Marcus du Sautoy (presenter) (2008). "The Genius of the East". The Story of Maths. BBC.
- Jim Al-Khalili (presenter) (2010). Science and Islam. BBC.
External links
- Hogendijk, Jan P. (January 1999). "Bibliography of Mathematics in Medieval Islamic Civilization".
- O'Connor, John J.; Robertson, Edmund F. (1999), "Arabic mathematics: forgotten brilliance?", MacTutor History of Mathematics Archive, University of St Andrews
- Richard Covington, Rediscovering Arabic Science, 2007, Saudi Aramco World
- List of Inventions and Discoveries in Mathematics During the Islamic Golden Age
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