f(x)=sinx平方+2根号3sinxcosx-cosx平方
=√3sin2x-cos2x
=2sin(2x-π/6)
1)
最大值=2
此时2x-π/6=2kπ+π/2
x=kπ+π/3
2)
函数在区间满足:2kπ-π/2