# How do you show that a function has a vertical asymptote?

##### 1 Answer
Apr 21, 2018

You have a vertical asymptote in $f \left(x\right)$, if for some $x = a$, ${\lim}_{x \to a} f \left(x\right) = \pm \infty$. In algebraic functions this happens when a factor in denominator tends to $0$.