举报
zhang-wei-na
y=sin^2 2X+√3sinxcosx-1=(1-cos2x)/2+√3/2*(2sinxcosx)-1
=√3/2*sin2x-1/2*cos2x-1/2
=sin2xcosπ/6-cos2xsinπ/6-1/2
=sin(2x-π/6)-1/2
-1<=sin(2x-π/6)<=1
-3/2<=y<=1/2
sin(2x-π/6)=-1
2x-π/6=2kπ-π/2
x=kπ-π/6
sin(2x-π/6)=1
2x-π/6=2kπ+π/2
x=kπ+π/3
得:
y最小值=-3/2,当x=kπ-π/6
y最大值=1/2,当x=kπ+π/3,