Ācārya Jayadeva is an early Indian mathematician, known only through a long aphoristic (Sūtra) quotation in 20 verses from an unknown work of his. In this passage, Jayadeva sets out, step by step, an ingenious method for solving the indeterminate equation of the form Nx2 ± C = y2. This quotation was extracted by Udayadivākara, an astronomer of Kerala, in his commentary called Sundarī on the Laghu‐bhāskārīya of Bhāskara I (b. 629). Udayadivākara flourished about AD 1073. This means that Jayadeva lived before that date.
The above extract was made in the context of an astronomical problem involving two simultaneous equations (1) 7y2 + 1 = z2 and (2) 8x + 1 = y2. Here, Udayadivākara states that the value of y in the first equation can be found by an ingenious method called varga‐prakṛti (lit. “square‐nature”) enunciated by Ācārya Jayadeva, and the value of x in the second equation by the method of inversion.
The extract from Jayadeva forms an account of varga‐prakṛtias he conceives it...
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