Bhaskara's lemma
"Bhaskara's" Lemma is an identity used as a lemma during the chakravala method. It states that: for integers formula_2 and non-zero integer formula_3. Proof. The proof follows from simple algebraic manipulations as follows: multiply both sides of the equation by formula_4, add formula_5, factor, and divide by formula_6. So long as neither formula_3 nor formula_4 are zero, the implication goes in both directions. (The lemma holds for real or complex numbers as well as integers.)