y=cos(x/3+π/4)的单调区间

问题描述:

y=cos(x/3+π/4)的单调区间

y=cos(x/3+π/4)
单调增区间:2kπ-π即:6kπ-15π/4单调减区间:2kπ即:6kπ-3π/4