index: click on a letter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A to Z index index: subject areas numbers & symbols sets, logic, proofs geometry algebra trigonometry advanced algebra & pre-calculus calculus advanced topics probability & statistics real world applications multimedia entries

L'Hôpital's Rule
L'Hospital's Rule

A technique used to evaluate limits of fractions that evaluate to the indeterminate expressions and . This is done by finding the limit of the derivatives of the numerator and denominator.

Note: Most limits involving other indeterminate expressions can be manipulated into fraction form so that l'Hôpital's rule can be used.

 L'Hôpital's Rule: If f and g are differentiable on an open interval containing a such that g(x) ≠ 0 for all x ≠ a in the interval, and if either and or and then Example: