## Calculus: Early Transcendentals 8th Edition

all real x, $x\ne\frac{\pi}{4}+n\pi$ (n is an integer)
The function is defined for all real x where the denominator $1-\tan x\ne0$. When $1-\tan x=0$, $\tan x=1, x=\frac{\pi}{4}+n\pi$ (n is an integer) $\therefore$ the domain is all real x, exluding $x=\frac{\pi}{4}+n\pi$ (n is an integer)