f(x)=cos(2x+60)+sin^2x
=cos2xcos60-sin2xsin60+sin^2x
=1/2*cos2x-√3/2sin2x+(1-cos2x)/2
=1/2*cos2x-√3/2sin2x+1/2-1/2cos2x
=-√3/2sin2x+1/2
-1