Michel Rolle

Early in any calculus course, the students meet the mean value theorem, with its standard proof by way of what is called Rolle's theorem. This theorem is named after Michel Rolle, who was born during the spring of 1652 in Ambert, in the south-central part of France.

Rolle was pretty much a self-educated person who, after working for some attorneys around Ambert, moved to Paris and worked as a copier of manuscripts and as, maybe, a bookkeeper. Though it was likely invented earlier, he is known today as the one who established the symbol

for the nth root of m. He published a book on the theory of equations, and in 1685, he was elected to the Académie Royale des Sciences.
Though his name is known to every student of calculus, he described the subject as, " . . . a collection of ingenious fallacies."

Rolle died in late 1719 in Paris.