Question

cos2x=?
A.cos^2x-sin^2x
B.2sin^2x-1
C.sin^2x-cos^2x
D.1-2sin^2x
check all that apply

Answer 1

What is the double angle formula for cosine? Or, by cos2x, do you mean to write cos^2(x)?
If it is cos(2x), look up the double angle formula for cosine and post it here.

Answer 2

@marissak