sinXsin(x-TT/3)的周期是什麼
问题描述：
sinXsin(x-TT/3)的周期是什麼
答
sinx*sin(x-π/3)=sinx*(sinx/2+√3cosx/2)
=(sinx)^2/2+√3sinxcosx/2
=(1-cos2x)/4+√3sin2x/4
=1/4-(1/2)cos(2x+π/3)
则最小正周期T=2π/2=π