# Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures

Living Edition
| Editors: Helaine Selin

Living reference work entry
DOI: https://doi.org/10.1007/978-94-007-3934-5_10293-1

Jayadeva was an Indian mathematician who lived before the eleventh century. He was a proponent of the cakravāla system involving the process of continuous fraction. We know next to nothing about his life or works. The only source of information about him is the Sundarī, a commentary on the Laghubhaskarīya of Bhāskara I by the Kerala mathematician Udayadivākara (CE 1073).

In the Sundarī, Udayadivākara gives an extract from a lost text of Jayadeva’s. It is 20 verses long, and proposes a novel method for the indeterminate equation or the so-called Pell’s equation, x2 − ay2 = b. The discussion and extract are occasioned by an astronomical problem that involves two simultaneous equations, (i) x2 – ay2 = b and (ii) x2 – ay2 = 1. The solution to this problem was dependent on the fact that the value of b in the first equation was always +1, −1, +2, −2, +4 or −4, and involved the method of varga prakti. According to Jayadeva, varga praktiis an equation in which the result of the square of...

## Keywords

Optimal Number Fraction Process Continuous Fraction Simultaneous Equation Easy Method
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.

## References

1. Hankel, H. (1874). Zur Geschichte der Mathematik in Alterum und Mittelalter (pp. 203–204). Leipzig, Germany: Terbner.Google Scholar
2. Selenius, C.-O. (1975). Rationale of the chakravāla process of Jayadeva and Bhaskara II. Historia Mathematica, 2, 167–184.
3. Shukla, K. S. (1954). Ācārya Jayadeva, The Mathematician. Gaṇita, 5, 1–20.Google Scholar