解由2kπ-π/2≤1/2x+π/3≤2kπ+π/2,k属于Z时,y是增函数,
即4kπ-5π/3≤x≤4kπ+π/3,k属于Z时,y是增函数,
即函数f(x)的单调递增区间[4kπ-5π/3,4kπ+π/3]k属于Z.