l'Hôpital's rule

${\lim }_{x\to a}\frac{f(x)}{g(x)}={\lim }_{x\to a}\frac{f^{\prime }(x)}{g^{\prime }(x)}$

L’Hôpital’s rule is used to handle indeterminate form in limits: $\frac{0}{0}$, $\frac{\infty }{\infty }$, $-\frac{\infty }{\infty }$.

• The rule only applies when the current limit is in indeterminate form.
• Show that the original limit is indeterminate before using the rule.