y=sin xsin(3π/2-x)=sinx(sin2π/3cosx-cos2π/3sinx)=√3/2sinxcosx+1/2(sinx)^2=√3/4*sin2x+1/4(1-cos2x)=√3/4*sin2x-1/4*cos2x+1/4=1/2(√3/2sin2x-1/2*cos2x)+1/4=1/2sin(2x-π/6)+1/4最小正周期T=2π/2=π...