How do you prove (cos^4x - sin^4x)/sin^2x=cot^2x-1cos4xsin4xsin2x=cot2x1?

1 Answer
Dec 5, 2015

Prove trig equation.

Explanation:

cos^4 x - sin^2 x = (cos ^2 x - sin^2 x( (cos^2 x + sin^2 x) = cos4xsin2x=(cos2xsin2x((cos2x+sin2x)=
= (cos@ x - sin^2 x).=(cosxsin2x). because (cos^2 x + sin^2 x) = 1
(cos^2 x - sin^2 x)/(sin^2 x) = cos^2 x/(sin^2 x) - sin^2 x/(sin^2 x) = cos2xsin2xsin2x=cos2xsin2xsin2xsin2x=
= cot^2 x - 1=cot2x1