Definition:Horizontal Asymptote

Definition

The horizontal line $y = L$ is a horizontal asymptote of the graph of a real function $f$ if and only if either of the following limits exist:

$\ds \lim_{x \mathop \to +\infty} \map f x$

$=$

$\ds L_1$

$\ds \lim_{x \mathop \to -\infty} \map f x$

$=$

$\ds L_2$

This article, or a section of it, needs explaining.
In particular: What relation do $L_1$ and $L_2$ have to $L$?
You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by explaining it.
To discuss this page in more detail, feel free to use the talk page.
When this work has been completed, you may remove this instance of {{Explain}} from the code.