BhÄskara (c. 600 ā c. 680) (commonly called Bhaskara I to avoid confusion with the 12th century mathematician BhÄskara II) was a 7th-century mathematician, who was the first to write numbers in the Hindu decimal system with a circle for the zero, and who gave a unique and remarkable rational approximation of the sine function in his commentary on Aryabhatta's work. This commentary, Äryabhaį¹Ä«yabhÄį¹£ya, written in 629 CE, is among the oldest known prose works in Sanskrit on mathematics and astronomy. He also wrote two astronomical works in the line of Aryabhata's school, the MahÄbhÄskarÄ«ya and the...