y=√3/2*(sinx*√3/3-cosx*√6/3)
令cosa=√3/3,a是锐角
则sina=√(1-cos²a)=√6/3
所以y=√3/2*(sinxcosa-cosxsina)
=√3/2*sin(x-a)
所以值域[-√3/2,√3/2]