2x≠kπ+π/2,==》x≠kπ/2+π/4,
x≠kπ+π/2,
且tan x≠0,==》x≠kπ,k∈Z.
∴函数的定义域是{x| x≠kπ/2+π/4,x≠kπ+π/2,且x≠kπ,k∈Z}