cos(2x+π/3)+sinx的平方
问题描述：
cos(2x+π/3)+sinx的平方
答
=cos(π/3)cos2x-sin(π/3)sin2x+(1-cos2x)/2
=(1/2)cos2x-(√3/2)sin2x+1/2-(1/2)cos2x
=1/2-(√3/2)sin2x