y=3sinx-√3cosx
=2√3(sinx*√3/2-cosx*1/2)
=2√3(sinx*cosπ/6-cosx*sinπ/6)
=2√3sin(x-π/6)
∵x∈［0,π］
∴x-π/6∈［-π/6,5π/6］
当x-π/6=-π/6时取得最小值2√3×（-1/2)=-√3
当x-π/6=π/2时取得最大值2√3×1=2√3
所以值域为[-√3,2√3]