函数f(x)=cos(2x-π/5)为减函数的区间是?

函数f(x)=cos(2x-π/5)为减函数的区间是?
函数f(x)=cos(2x-π/5)为减函数的区间是?

函数f(x)=cos(2x-π/5)为减函数的区间是?
0+2kπ

2kπ＜2x-π/5＜2kπ+π
2kπ+π/5＜2x＜2kπ+6π/5
kπ+π/10＜x＜kπ+3π/5
∴x∈[kπ+π/10，kπ+3π/5]