Prove the identity of: 1-sin^2 x/cosx = cosx

Answer 1

(1 - sin^2x)/cosx = cosx

multiply both sides by cosx to get

1 - sin^2x = cos^2

1 = sin^2x + cos^2x which is a version of the Pythagorean Theorem x^2 + y^2 = 1^2 for a unit circle