Jyeṣṭhadeva

| birth_place = | death_date = | death_place = | body_discovered = | death_cause = | resting_place = | resting_place_coordinates = | nationality = | citizenship = | other_names = | known_for = Authorship of Yuktibhāṣā | education = | alma_mater = | employer = | notable works = Yuktibhāṣā, Drkkarana | occupation = Astronomer-mathematician | years_active = | height = | title = | term = | predecessor = | successor = | party = | opponents = | boards = | spouse = | partner = | children = | parents = | relations = Parangngottu (Sanskritised as Parakroda) family | callsign = | awards = | signature = | signature_alt = | website = | footnotes = Pupil of Damodara, contemporary of Nilakantha Somayaji, teacher of Achyuta Pisharati }}

Jyeṣṭhadeva () was an astronomer-mathematician of the Kerala school of astronomy and mathematics founded by Madhava of Sangamagrama (). He is best known as the author of ''Yuktibhāṣā'', a commentary in Malayalam of Tantrasamgraha by Nilakantha Somayaji (1444–1544). In Yuktibhāṣā, Jyeṣṭhadeva had given complete proofs and rationale of the statements in Tantrasamgraha. This was unusual for traditional Indian mathematicians of the time. The Yuktibhāṣā is now believed to contain some elements of calculus like Taylor and infinity series of some trigonometric functions.However they did not combine many differing ideas under the two unifying themes of the derivative and the integral, show the connection between the two, and turn calculus into the powerful problem-solving tool we have today.Jyeṣṭhadeva also authored ''Drk-karana,'' a treatise on astronomical observations.

According to K. V. Sarma, the name "Jyeṣṭhadeva" is most probably the Sanskritised form of his personal name in the local language Malayalam. Provided by Wikipedia