l'Hôpital, Guillaume François Antoine, Marquis de
l'Hôpital, Guillaume François Antoine, Marquis de (1661–1704)
French mathematician who in 1696 produced the first textbook on differential calculus. This, and a subsequent book on analytical geometry, were standard texts for much of the eighteenth century. The first contains l'Hôpital's rule, known to be due to Jean Bernouilli, who is thought to have agreed to keep the Marquis de l'Hôpital informed of his discoveries in return for financial support.