f(x)=cosx(cosxcosπ/3+sinxsinπ/3)=1/2*cos²x+√3/2*sinxcosx=1/2*(1+cos2x)/2+√3/2*sin2x/2=√3/4*sin2x+1/4*cos2x+1/4=1/2*(sin2xcosπ/6+cos2xsinπ/6)+1/4=1/2*sin(2x+π/6)+1/4所以T=2π/2=π即sin(2x+...