Born: about 600 in (possibly) Saurastra (modern Gujarat state), India
Died: about 680 in (possibly) Asmaka, India
There are other references to places in India in Bhaskara's writings. For example he mentions Valabhi (today Vala), the capital of the Maitraka dynasty in the 7th century, and Sivarajapura, which were both in Saurastra which today is the Gujarat state of India on the west coast of the continent. Also mentioned are Bharuch (or Broach) in southern Gujarat and Thanesar in the eastern Punjab which was ruled by Harsa for 41 years from 606. Harsa was the preeminent ruler in north India through the first half of Bhaskara I's life. A reasonable guess would be that Bhaskara was born in Saurastra and later moved to Asmaka.
Bhaskara I was an author of two treatises and commentaries to the work of Aryabhata I. His works are the Mahabhaskariya , the Laghubhaskariya and the Aryabhatiyabhasya . The Mahabhaskariya is an eight chapter work on Indian mathematical astronomy and includes topics which were fairly standard for such works at this time. It discusses topics such as: the longitudes of the planets; conjunctions of the planets with each other and with bright stars; eclipses of the sun and the moon; risings and settings; and the lunar crescent.
Bhaskara I included in his treatise the Mahabhaskariya three verses which give an approximation to the trigonometric sine function by means of a rational fraction. These occur in Chapter 7 of the work. The formula which Bhaskara gives is amazingly accurate and use of the formula leads to a maximum error of less than one percent. The formula is
|x = 0||formula = 0.00000||sin x = 0.00000||error = 0.00000|
|x = π/20||formula = 0.15800||sin x = 0.15643||error = 0.00157|
|x = π/10||formula = 0.31034||sin x = 0.30903||error = 0.00131|
|x = 3π/20||formula = 0.45434||sin x = 0.45399||error = 0.00035|
|x = π/5||formula = 0.58716||sin x = 0.58778||error = -0.00062|
|x = π/4||formula = 0.70588||sin x = 0.70710||error = -0.00122|
|x = π/10||formula = 0.80769||sin x = 0.80903||error = -0.00134|
|x = 7π/20||formula = 0.88998||sin x = 0.89103||error = -0.00105|
|x = 2π/5||formula = 0.95050||sin x = 0.95105||error = -0.00055|
|x = 9π/20||formula = 0.98753||sin x = 0.98769||error = -0.00016|
|x = π/2||formula = 1.00000||sin x = 1.00000||error = 0.00000|
One of the approximations used for π for many centuries was √10. Bhaskara I criticised this approximation. He regretted that an exact measure of the circumference of a circle in terms of diameter was not available and he clearly believed that π was not rational.
In , ,  and  Shukla discusses some features of Bhaskara's mathematics such as: numbers and symbolism, the classification of mathematics, the names and solution methods of equations of the first degree, quadratic equations, cubic equations and equations with more than one unknown, symbolic algebra, unusual and special terms in Bhaskara's work, weights and measures, the Euclidean algorithm method of solving linear indeterminate equations, examples given by Bhaskara I illustrating Aryabhata I's rules, certain tables for solving an equation occurring in astronomy, and reference made by Bhaskara I to the works of earlier Indian mathematicians.
Article by: J J O'Connor and E F Robertson
MacTutor History of Mathematics