contestada

use the fundamental identities to fully simplify the expression
3sin^3 x * csc x + cos^2 x + 2 cos(-x) * cos x

I simplified it until this
3sin^2 x + cos^2 x +2cos^2(-x)*cos(x)

I know the answer is suppose to be 3 but I don't know how to simplify further to get to 3