Florimond de Beaune

Florimond de Beaune (7 October 1601, Blois – 18 August 1652, Blois) was a French jurist^[1] and mathematician, and an early follower of René Descartes.^[2] R. Taton calls him "a typical example of the erudite amateurs" active in 17th-century science.^[1]

In a 1638 letter to Descartes, de Beaune posed a problem that can be reformulated in modern notation as solving the differential equation

${\displaystyle {\frac {\operatorname {d} y}{\operatorname {d} x}}={\frac {\alpha }{y-x}}}$

now seen as the first example of the inverse tangent method of deducing properties of a curve from its tangents.^[3][4]

His Tractatus de limitibus aequationum was reprinted in England in 1807;^[5] in it, he finds upper and lower bounds for the solutions to quadratic equations and cubic equations, as simple functions of the coefficients of these equations.^[2] His Doctrine de l'angle solide and Inventaire de sa bibliothèque were also reprinted, in Paris in 1975.^[1] Another of his writings was Notae breves, the introduction to a 1649 edition of Descartes' La Géométrie.^[6]