sin^2 x + cos^2 x = 1
now subtract sin^2 x from both sides
cos^2 x = 1 - sin^2 x
Figured it out nevermind!!! I have another question though.
I put 1-sin(x) and of course it was marked wrong. I was given advice to refer to the Identity of sin^2 x + cos^2 x=1. How can I apply that or is that the answer itself?