Mathematician:Jean-Robert Argand

Amateur mathematician of Swiss origin, also an accountant and bookseller, best known for the Argand diagram.

Also published, in 1814, the first complete and rigorous proof of the Fundamental Theorem of Algebra.

Nationality
Swiss

History

 * Born: 18 July 1768, Geneva, Switzerland
 * Died: 13 Aug 1822, Paris, France

Theorems and Definitions

 * Argand diagram

Books and Papers

 * 1806: Essai sur une manière de représenter les quantités imaginaires dans les constructions géométriques (Essay on a method of representing imaginary quantities) (republished 1813 in the French journal Annales de Mathématiques)
 * 1814: Réflexions sur la nouvelle théorie d'analyse (Reflections on the new theory of analysis)