函数y=3-2cos(2/3 x+π/3)最大值为5.此时自变量x的取值集合是?

y=3-2cos(2/3 x+π/3)最大值为5,
即cos(2/3
x+π/3)=-1,2x/3+π/3=2kπ+π,
解得x=3kπ+π(k∈Z)
所求的集合为｛x| x=3kπ+π(k∈Z)｝