The field of mathematics is incomplete without the generous contribution of an Indian mathematician named, Brahmagupta. Besides being a great mathematician he was an even brilliant astronomer who wrote several books on these subjects. The doctrine of Barhama entitled the Brāhmasphuṭasiddhānta, is one of his early works on mathematics and astronomy. His major contribution to mathematics includes the introduction of number zero in computation.
According to himself, Brahmagupta was born in 598 CE and was the follower of Shaivism. During the rule of Chapa dynasty ruler, Vyagrahamukha, he lived in Bhillamala according to historian, yet there is no conclusive proof of that. Other sociologists believed he might have belonged to Multan region. Bhillamala was the capital of Gurjaradesa, currently known as Gujrat. It was the hub of all mathematical and astronomical learning. Bharmagupta assumed the position of an astronomer at Brahmapaksha school.
At a young age of 30, he wrote the improved treatise of Brahma called Brāhmasphuṭasiddhānta. It is speculated that it was the revision of the siddhanta he received from the school. He brought originality to the treatise by adding a great deal of new material to it. The book is written in arya-meter comprising 1008 verses and 24 chapters. An enormous amount of material is found on astronomy, while it also includes chapters on mathematics, trigonometry, algorithms and algebra.
After completing his work in Bhillamala, he moved to Ujjain which was also considered a chief location with respect to studies in astronomy. Aside from his revision of Brahma treatise, at the mature age of 67, he wrote another foremost work in mathematics entitled, Khanda-khādyaka. This text is a practical manual of Indian astronomy which is meant to guide students.
In his Brahma treatise, Brahmagupta criticized contemporary Indian astronomer on their different opinion. The rift between the mathematicians was created based on their varying ways of applying mathematics to physical world. Brahma had different views on astronomical parameters and theories. In his books he dedicated several chapters critiquing mathematical theories and their application.
There are numerous science historians who made testimony to his great scientific contribution. According to George Sarton, he was a great scientist of his race. In Medieval Europe Indian arithmetic was called “Modus Indoram” which means method of the Indians. He called multiplication gomutrika in his Brahmasphutasiddhanta. His work was further explored by Bhāskara II who held Brahmagupta at an elevated position for his immense contribution to mathematics. His work was further simplified and added illustrations to by Prithudaka Svamin. In addition to that his work was commented upon by Lalla and Bhattotpala in the eighth and ninth century. When Sindh was conquered by Arabs, his work was translated into Arabic by an astronomer, Muhammad al-Fazari which led to the use of decimal number system in written discourse.
Some of the major contribution to the field of astronomy by Brahmagupta are solar and lunar eclipse calculations and methods for calculating the position of heavenly bodies over time. Moreover, in a chapter titled Lunar Cresent he criticized the notion that the Moon is farther from the Earth than the Sun which was mentioned in Vedic scripture. He was of the view that the Moon is closer to the Earth than the Sun based on its power of waxing and waning. The illumination of the moon depends on the position and angle of Sunlight that hits the surface of the moon.