f（x）=√3sin²x+sinxcosx=√3/2(1-cos2x)+1/2sin2x=√3/2+sin(2x-π/6)
f（x）=0,sin(2x-π/6)=-√3/2 ,2x-π/6=π/3 ,x=π/4 ,2x-π/6=2π/3 ,x=5π/12