# Math Help - identity

1. ## identity

((sin x)^2 - (cos x)^2) / (sin x- cos x) = sin x + cos x

I want to change the LHS only.

2. Originally Posted by Stuck Man
((sin x)^2 - (cos x)^2) / (sin x- cos x) = sin x + cos x

I want to change the LHS only.
Remember $a^2-b^2=(a+b)(a-b)$? If so, apply that to the LHS, then cancel the common factor $a-b$ of numerator and denominator.