f(x)=2sin²x/2+cos(x-π/3）
=1-cosx+cosxcosπ/3+sinxsinπ/3
=1-cos(x+π/3)
所以f(x)的最大值是2即当cos(x+π/3）=-1时.
其单调增区间是2kπ-π/3≤x≥2kπ+2π/3