Johann Bernoulli rule (l'Hopital's rule) 1

G. F. de l'Hopital (1661-1704) - French mathematician, a capable student of Johann Bernoulli, a marquis for whom the latter wrote the first textbook of analysis in the years 1691-1692. The portion of this textbook devoted to differential  calculus was published in slightlyvaltered form by l'Hopital under his own name.
Thus "l'Hopital's rule" is really due to Johann Bernoulli.