Alī ibn Ahmad al-Nasawī

Who was Alī ibn Ahmad al-Nasawī?

ʿAlī ibn Aḥmad al-Nasawī was a Persian mathematician from Khurasan, Iran. He flourished under the Buwayhid sultan Majd al-dowleh, who died in 1029-30AD, and under his successor. He wrote a book on arithmetic in Persian, and then Arabic, entitled the "Satisfying on Hindu Calculation". He also wrote on Archimedes's lemmata and Menelaus's theorem. where he made corrections to The Lemmata as translated into Arabic by Thabit ibn Qurra, which was last revised by Nasir al-Din al-Tusi.

Al-Nasawī's arithmetic explains the division of fractions and the extraction of square and cubic roots almost in the modern manner. Al-Nasawī replaces sexagesimal by decimal fractions.

Al-Nasawī's criticises earlier authors, but in many cases invalidly. His work was not original, and he sometimes writes of matters that he does not understand, e.g. "borrowing" in subtraction.

Ragep and Kennedy also give an analysis of a mid-12th-century manuscript in which a summary of Euclid's Elements exists by al-Nasawī.