He is a scientist at an observatory and learning center established in Samarkand by the prince Ulugh Beg, a grandson of the Mongol conqueror Tamerlane.
Al-Kashi worked at many areas of science —astronomy, algebra and geometry. The first known scientific event in Al-Kashi’s life is his observation of an eclipse of the moon, made in Kashan on June 2, 1406. The day is precise, since Al-Kashi dated many of his works with the exact date on which they were completed.
In 1410-1411, he wrote Mukhtasar dar ilm-i hay’at-Compendium of the science of astronomy dedicated to Sultan Iskandar, one of the rulers of Timurid dynasty.
In 1413-1414, al-Kashi wrote Khaqani zij and dedicated it to Ulugh Beg. In the introduction of this book al-Kashi complains about living in poverty while working on mathematics and astronomy, and he says he could not have completed this work without Ulugh Beg’s support.
Kashi’s work “Nuzhat al-hada’iq’ completed in 1416, described an instrument ‘tabaq al-manatiq’ (equatorium) used for the determination ofthe position of the planets (longitude and latitude) on the ecliptic and a second instrument ‘lauh al-ittisalat’, used to compute the conjunctions of the planets.
On March 2, 1427, Al-Kashi completed a monumental book in Arabicon arithmetic called Mift ̄ah al-his ̄ab. His book Mift ̄ah al-his ̄ab (Key to Arithmetic) provides sufficient knowledge of mathematics for those who are working on astronomy, surveying, architecture, accounting and trading.
Al-Kashi provided accurate trigonometric tables. He also expressed the theorem in a suitable form for the modern usage. In French, the law of cosines in named theorem d'Al-Kashi after al-kashi unification of the exiting works on the subject.
All great discoveries of Al-Kashi were unknown in Europe and only in the 19th and 20thcenturies they were studied by the historians of science.
The works of al-Kashi
