# Finding Vertical Asymptote with limits

1. Sep 23, 2009

### Loppyfoot

How do I find a vertical asymptote of a function by using limits? I can find the HA by taking the limit, but how do I get the VA? What if the denominator is a square root?

FIGURED OUT: I need to evaluate the limit as x approaches a from the right and left.

Last edited: Sep 23, 2009
2. Sep 23, 2009

### lanedance

i think you need to give more detail for clairty & show your problem/working

3. Sep 23, 2009

### Elucidus

A function is said to have a vertical asymptote at x = a if the limit of f(x) diverges to +/- infinity as x approaches a from either the left or the right (or both).

So to find vert. asymptotes look for where you'd have an infinitely divergent limit (like zero denominators with nonzero numerators amongst others).

--Elucidus