f(x)=2sinxcosx+2√3cos²x-√3=2sinxcosx+√3(2cos²x-1)=sin2x+√3cos2x=2sin(2x+π/3)最小正周期T=2π/2=π，振幅A＝2递减区间是2kPai+Pai/2<=2x+Pai/3<=2kPai+3Pai/2即有[kPai+Pai/12,kPai+7Pai/12]
