 Bhaskara (c. 600 – c. 680)commonly called Bhaskara I to avoid confusion with the 12th century mathematician Bhaskara II) was a 7th century Indian mathematician, who was apparently the first to write numbers in the Hindu-Arabic 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 Aryabhata’s work. This commentary, Aryabhatiyabhasya, written in 629 CE, is the oldest known prose work in Sanskrit on mathematics and astronomy. He also wrote two astronomical works in the line of Aryabhata’s school, the Mahabhaskariya and the Laghubhaskariya.

Bhaskara I wrote two treatises, the Mahabhaskariya and the Laghubhaskariya. He also wrote commentaries on the work of Aryabhata I entitled Aryabhatiyabhasya. The Mahabhaskariya comprises of eight chapters dealing with mathematical astronomy. The book deals with topics such as: the longitudes of the planets; association of the planets with each other and also with the bright stars; the lunar crescent; solar and lunar eclipses; and rising and setting of the planets. Bhaskara I suggested a formula which was astonishingly accurate value of Sine.
The formula is: sin x = 16x (p – x)/[5p2 – 4x (p – x)]

Bhaskara I wrote the Aryabhatiyabhasya in 629,, which is a commentary on the Aryabhatiya written by Aryabhata I. Bhaskara I commented only on the 33 verses of Aryabhatiya which is about mathematical astronomy and discusses the problems of the first degree of indeterminate equations and trigonometric formula. While discussing about Aryabhatiya he discussed about cyclic quadrilateral. He was the first mathematician to discuss about quadrilaterals whose four sides are not equal with none of the opposite sides parallel.

For many centuries, the approximate value of p was considered v10. But Bhaskara I did not accept this value and believed that p had an irrational value which later proved to be true. Some of the contributions of Bhaskara I to mathematics are: numbers and symbolism, the categorization of mathematics, the names and solution of the first degree equations, quadratic equations, cubic equations and equations which have more than one unknown value, symbolic algebra, the algorithm method to solve linear indeterminate equations which was later suggested by Euclid, and formulated certain tables for solving equations that occurred in astronomy.