Gilles Personne De Roberval
Roberval, Gilles Personne De
(real surname Per-sonier). Born Aug. 8, 1602, in Roberval, near Beauvais; died Oct. 27, 1675, in Paris. French mathematician. Member of the Académie des Sciences (1666).
Simultaneously with B. Cavalieri, Roberval developed the method of indivisibles, which is conceptually similar to the analysis of infinitesimals. Roberval used this method to determine arc lengths of many curves, areas of figures with curvilinear boundaries, and volumes of several solids. He discovered a method for drawing tangents to curves wherein the curve is treated as the path of a point in complex motion.