前面是2cos²x吧∵2cos²x-1=cos2x,cos(3π/2+2x)=sin2x∴fx=2cos²x+√3cos(3π/2+2x)-1=cos2x+√3sin2x=2(√3/2sin2x+1/2cos2x) (提取2）=2（sin2xcosπ/6+cos2xsinπ/6) (引入辅助角π/6)=2sin(2x+π...