题目内容：

y=cos2x+sinx(sinx+cosx) 化简

优质解答

y=cos2x+sinx(sinx+cosx)
= cos2x + sin²x + sinxcosx
=cos2x +（1 - cos2x）/2 + sin2x/2
=0.5 + 0.5cos2x + 0.5sin2x
=0.5 + √2sin（2x + π/4）/2