Al-Jayyani

Abu Abd Allah Muhammad ibn Muadh Al-Jayyani, shortened to Al-Jayyani (989, Cordova, Al-Andalus – 1079, Jaen, Al-Andalus) was an Arab mathematician from Al-Andalus (in present-day Spain). Al-Jayyani wrote important commentaries on Euclid's Elements and he wrote the first treatise on spherical trigonometry. Little is known about his life. Confusion exists over the identity of Al-Jayyani the scholar and Al-Jayyani the mathematician. It is unknown whether they are the same person.

Al-Jayyani wrote the first treatise on spherical trigonometry, entitled The book of unknown arcs of a sphere, although earlier mathematicians, such as Menelaus of Alexandria, did have books that dealt with spherical trigonometry. Al-Jayyani's treatise "contains formulae for right-handed triangles, the general law of sines, and the solution of a spherical triangle by means of the polar triangle." This treatise later had a "strong influence on European mathematics", and his "definition of ratios as numbers" and "method of solving a spherical triangle when all sides are unknown" are likely to have influenced Regiomontanus.

See also

• List of Arab scientists and scholars
• Islamic mathematics

References