How do you simplify cot^2x - cot^2x cos^2xcot2xcot2xcos2x?

1 Answer
May 25, 2018

cos^2 xcos2x

Explanation:

Given: cot^2x - cot^2 x cos^2xcot2xcot2xcos2x

Factor: cot^2x (1 - cos^2x) cot2x(1cos2x)

Use the Pythagorean trigonometric identity: sin^2x + cos^2x = 1sin2x+cos2x=1

Rearrange the identity: sin^2x = 1 - cos^2xsin2x=1cos2x

cot^2x (1 - cos^2x) = cot^2x sin^2xcot2x(1cos2x)=cot2xsin2x

Use the identity: cot x= (cos x)/(sin x)cotx=cosxsinx

Realize that cot^2x = (cot x)^2cot2x=(cotx)2

cot^2x (1 - cos^2x) = (cos^2 x)/cancel(sin^2 x) cancel(sin^2x) = cos^2x