Question

Which of the following are identities? Check all that apply.

A. sin^2x - cos^2x = 1

B. sin^2x = 1 - cos^2x

C. tan^2x = 1 + sec^2x

D. cot^2x = csc^2x - 1

Answer 1

the correct identities are:

1 + tan^2x = sec^2x
1 + cot^2x = csc^2x
sin^2x + cos^2x = 1

which correspond to B and D

Answer 2

Thanks a lot :)