Vatasseri Parameshvara (വടശ്ശേരി പരമേശ്വരന്) (1360-1425) was a major
Indian mathematicianof Madhava of Sangamagrama's Keralaschool, as well as an astronomerand astrologer. He presented a series form of the sinefunction that is equivalent to its Taylor seriesexpansion.
Paramesvara was born into a
Hindufamily who were astrologers and astronomers. The family home was Vatasseri (also called Vatasreni) in the village of Alattur, Kerala. Paramesvara's coordinates with respect to Ujjain puts it at latitude 10 51' north. It is on the north bank of the river Nila, at its mouth.
Parameshvara's teachers included Rudra, Madhava and
Narayana Pundit.Parameshvara wrote many commentaries on many mathematical and astronomical works, such as those by Bhaskara Iand Aryabhatta.
He made eclipse observations over a 55 year period, and constantly attempted to compare these with the theoretically computed positions of the planets. He revised planetary parameters based on his observations.
Paramesvara most significant contributions is his mean value type formula for inverse interpolation of sine. He is the first mathematician to give the
radiusof circlewith inscribed cyclic quadrilateral, an expression that is normally attributed to Lhuilier(1782), 350 years later. With the sides of the cyclic quadrilateral being a, b, c and d, the radius r of the circumscribed circle calculates to:
History of calculus
Melpathur Narayana Bhattathiri
Wikimedia Foundation. 2010.