L'Hopital's rule

noun

L'Ho·​pi·​tal's rule ˌlō-pē-ˈtälz- 

variants or L'Hospital's rule

: a theorem in calculus: if at a given point two functions have an infinite limit or zero as a limit and are both differentiable in a neighborhood of this point then the limit of the quotient of the functions is equal to the limit of the quotient of their derivatives provided that this limit exists

Word History

Etymology

Guillaume de l'Hôpital †1704 French mathematician

First Known Use

1918, in the meaning defined above