Question

求详细的化简过程（尽量完整,

Answer 1

(1)y=(sinx+cosx)^2+2cos^2x=sin^2x+2sinx*cosx+cos^2x+cos2x-1=sin2x+cos2x=根号(2)sin(2x+pi/4)

(2)y=cos^4x-2sinx*cosx-cos^4x=(cos^2x-sin^2x)(cos^2x+sin^2x)-sin2x=cos2x-sin2x=根号(2)cos(2x+pi/4)