Prove that the following identity is true. sin x tan x sin x cos x sin x - COs X cos x 2 cos x We begin on the right side of the equation by factoring the numerator and denominator. We can then use a Pythagorean Identity in the denominator and reduce. We can then use the ratio identity, and then factor the denominator. Finally we simp reducing the common factor. sin x(sin x + cos x) sin xsin x cos x coS x1 cos x 2 cos x sin x(sin x + cos x) sin xcos2 COS X sin x cos x sin x sin2 х — COS X cos x sin x = tan x sin x sin x cos x = tan x ' (sin x - cos x) tan x sin x - cos x