Guillaume de l'Hôpital

Guillaume François Antoine, Marquis de l'Hôpital (1661 - February 2, 1704) was a French mathematician. He is perhaps best known for the rule which bears his name for calculating the limiting value of a fraction whose numerator and denominator approach zero.

He is also the author of the first known calculus textbook. Published in 1696, the text includes the lectures of his teacher, Johann Bernoulli, in which Bernoulli discusses the indeterminate form 0/0.

His name is also spelled l'Hospital. The circumflex in "l'Hôpital" is a neologism; it was not in use at the time l'Hôpital was alive.