born Aug. 17, 1601, Beaumont-de-Lomagne, France
died Jan. 12, 1665, Castres
French mathematician.
Of Basque origin, Fermat studied law at Toulouse and developed interests in foreign languages, Classical literature, ancient science, and mathematics. A jurist by profession, he produced major mathematical breakthroughs independently and collaboratively. A contemporary of René Descartes , he discovered independently the basic principles of analytic geometry , but, because Fermat's work was published posthumously, the field became known as Cartesian geometry. He found equations for tangent line s to curves through processes equivalent to differentiation and was coauthor (with Blaise Pascal ) of probability theory . His work in number theory , especially divisibility, led to some of its most important theorems. He seldom demonstrated his results, which led to a centuries-long quest to prove a famous conjecture that Fermat claimed was easily shown (see Fermat's last theorem ).
Fermat, portrait by Roland Lefèvre; in the Narbonne City Museums, France
By courtesy of the Musees de la Ville de Narbonne, France