Cauchy, Augustin Louis (1789-1857)
French mathematician, born in Paris, and educated at the Ecole Polytechnique. Cauchy was appointed professor simultaneously at the Ecole Polytechnique, the University of Paris, and the College de France. In 1848 he was made Professor of Mathematical Astronomy at the University of Paris.
Cauchy verified the existence of recurrent elliptic functions, gave the first impetus to the general theory of functions, and laid the foundation for the modern treatment of the convergence of infinite series. He perfected the method of integration of linear differential equations (see Calculus), invented the calculus of residues, and in general was one of the leaders of the 19th century in infusing vigour into analysis. He also gave his attention to the propagation of light and the theory of elasticity.

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