La·grange 
(lə-grānj, -gränj, lä-gräɴzh), Comte Joseph Louis 1736-1813.
(lə-grānj, -gränj, lä-gräɴzh), Comte Joseph Louis 1736-1813. French mathematician and astronomer. He developed the calculus of variations (1755) and made a number of other contributions to the study of mechanics.