f(x)=√3sin2x+2cosx+m
f '(x)=2√3cos(2x)-2sin(x)=2√3(1-2sin^2(x))-2sin(x)=2√3-4√3sin^2(x)-2sin(x)
2√3sin^2(x)+sin(x)-√3=0
sin(x)=-√3/2 sin(x)=√3/3
取最大值时,sin(x)=√3/3,cos(x)=√6/3 sin(2x)=2*√3/3*√6/3=2√2/3
√3*2√2/3+2*√6/3+m=6
∴m=6-4√6/3
取最小值时,sin(x)=-√3/2,cos(x)=1/2 sin(2x)=-√3/2 或 cos(x)=-1/2 sin(2x)=+√3/2 (舍去)
最小值为:3*(-√3/2)+2*(1/2)+6-4√6/3≈ 1.1359