f(x)=sinx/3cosx/3+√3cos²x/3-√3/2 两倍角公式=1/2sin2x/3 + (√3/2)(cos2x/3 +1)-√3/2 =1/2sin2x/3 +√3/2cos2x/3 =cosπ/3sin2x/3 +sinπ/3cos2x/3=sin(2x/3 +π/3)周期:T=2π/(2/3)=3π,对称中心:2x/3 +...