(Muhammad ibn Musa al-Khwarizmi)

Arab mathematician, b. c. **780** (Khwarizm), d. c. **850**.

Muhammad ibn Musa was born in Khwarizm, today's Khiva south of the Aral Sea and is known in history as al-Khwarizmi. A mathematician and astronomer, he lived and worked in Baghdad during the first golden age of Arabic science under the caliphs al-Ma'mun and al-Mu'tasim. Several works of Al-Khwarizmi are known. He wrote the Al-Khwarizmi's fame as a scientist derives from his achievements in mathematics. His work on arithmetic was translated into Latin in the 12th century, and although the original is lost, the Latin translation Al-Khwarizmis' other work, Al-Khwarizmi also published astronomical and trigonometric tables based mainly on an Arabic translation of the Indian astronomical work |

The ax where all numbers are positive. The solutions to these equations are given as algorithms, and their proofs are given through geometrical argument. As an example, al-Khwarizmi solves an equation of the fourth canonical type as follows: "Let the square and ten roots be equal to 39. [In other words, the square of the unknown and ten times the unknown equals 39, or |

Portrait: postage stamp of the USSR, 1983; public domain

Illustration: a page from the *Kitab al-jabr wa l-muqabala,* J. L. Espositio (ed): Oxford History of Islam, Oxford University Press, Oxford, 1999, ISBN 0195107993; public domain *(Wikipedia)*

Statue of al-Khwarizmi in front of the Faculty of Mathematics of Amirkabir University of Technology in Tehran, Iran.

Photo: M. Tomczak; Creative Commons license.

Benoît, P. and F. Micheau (1995) The Arab Intermediary. In: M. Serres (editor): *A History of Scientific Thought, Elements of a History of Science.* Blackwell, Oxford, 191 - 221. (Translation of *Éléments d'Histoire des Sciences,* Bordas, Paris, 1989)