History of Hindu Mathematics: A Source Book v2.c17.s25.6

v2.c17.s25.6

Thus the solution is : \begin{align*} x &= P(m² + n²), \\ y &= P(m² - n²), \end{align*} where P = ((m² + n²) + (m² - n²))/([½(m² + n²) - (m² - n²)]²), m, n being any rational numbers.