√3sin2x+cos2x+a =2sin(2x+π/6)+a

问题描述:

√3sin2x+cos2x+a =2sin(2x+π/6)+a
怎么推的

√3sin2x+cos2x+a =2(√3/2*sin2x+1/2*cos2x)+a
=2(sin2x*cosπ/6+sinπ/6*cos2x)+a
=2sin(2x+π/6)+a