Prove that the equation is an identity:

Question

cot4theta - csc4theta = -cot sq theta - csc sq theta

How ??

Answer 1

cot^4 - csc^4
= (cot^2 - csc^2)(cot^2 + csc^2)
= (-1)(cot^2 + csc^2)
= -cot^2 - csc^2

remember csc^2 = 1 + cot^2 ??