Brahmadeva (1060–1130) was an Indian mathematician. He was the author of Karanaprakasa, which is a commentary on the Aryabhatiya by Aryabhata. Its contents deal partly with trigonometry and its applications to astronomy.
Brahmadeva was the son of Candrabudha. The family came from the Mathura district of Uttar Pradesh in northern India. He was born into the Brahman caste which meant he was from the highest ranking caste of Hindu priests. The Brahman caste had a strong tradition of education so Brahmadeva would have received one of the best educations of men of his time.
We have only one work by Brahmadeva and this is Karanaprakasa which is a commentary on the Aryabhatiya by Aryabhata I. Brahmadeva’s work is in nine chapters and it follows the contents of the original Aryabhatiya. Topics covered include the longitudes of the planets, problems relating to the daily rotation of the heavens, eclipses of the sun and the moon, risings and settings, the lunar crescent, and conjunctions of the planets.
The work contains some contributions to trigonometry, motivated by its application to mathematical astronomy. It is this aspect of the work which is mentioned by Gupta in.
Different commentaries on the Aryabhatiya achieved popularity in different parts of India. Brahmadeva’s commentary seems to have been particularly popular in Madras, Mysore and Maharastra. The more important commentaries on the Aryabhatiya became the basis for further commentaries and indeed this is what happened to the Karanaprakasa. Commentaries on Brahmadeva’s work continued to appear up to the seventeenth century.