正弦函数的增区间是【2kπ-π/2,2kπ+π/2】,k∈Z
∴ 2kπ-π/2≤x/2+π/3≤2kπ+π/2,k∈Z
即 2kπ-5π/6≤x/2≤2kπ+π/6,k∈Z
即 4kπ-5π/3≤x≤4kπ+π/3,k∈Z
即增区间是【4kπ-5π/3,4kπ+π/3】,k∈Z