Proof of special case of l'Hôpital's rule
L'Hôpital's rule helps us find limits in the form where direct substitution ends in the indeterminate forms or .
The rule essentially says that if the limit exists, then the two limits are equal:
The AP Calculus course doesn't require knowing the proof of this fact, but we believe that as long as a proof is accessible, there's always something to learn from it. In general, it's always good to require some kind of proof or justification for the theorems you learn.