Legendre, Adrien Marie

Legendre, Adrien Marie (ädrēăN` märē` ləzhäN`drə), 1752–1833, French mathematician. He is noted especially for his work on the theory of numbers, on which he wrote an essay (1798) containing the law of quadratic reciprocity as well as several supplements, all later incorporated in a definitive work, Théorie des nombres (1830). The results of his long study of elliptic integrals appeared in Traité des fonctions elliptiques (3 vol., 1825–32). He invented independently of C. F. Gauss, and was the first to state in print (1806), the method of least squares, and he collaborated in drawing up centesimal trigonometric tables. He taught at the École militaire, Paris, and at the École normale and was associated with the bureau of longitudes from 1812. His Éléments de géométrie (1794, tr. 1867) was an influential textbook.