How so you tell if the asymptotes are horizontal or vertical?

Question

Okay, so when you graph a rational function, how do you determine whether the asymptotes are horizontal or vertical?

Answer 1

If a function goes to infinity at a finite point, the asymptote is vertical. E.g. 1/x -> inf as x -> 0

If a function goes to a finite value at infinity, the asymptote is horizontal. E.g. 1/(1 + x^2) -> 1 as x -> inf