Question

Which of the following equations are identities? Check all that apply.
A. cot^2x + csc^2x = 1
B. sin^2x = 1 - cos^2x
C. tan^2x = sec^2x - 1
D. sin^2x - cos^2x = 1

Answer 1

B,C

Answer 2

memorize your identities, i guarantee you you will need them.