函数y=sin(x+π/4)的单调区间请问二楼详细过程是什么

函数y=sin(x+π/4)的单调区间
请问二楼详细过程是什么

(-3π/4+2kπ ,π/4+2kπ)单增
(π/4+2kπ ,5π/4+2kπ)单减

-π/2+2kπ≤x+π/4≤π/2+2kπ
-3π/4+2kπ≤x≤π/4+2kπ
∴[-3π/4+2kπ,π/4+2kπ]