Lagrange, Joseph (1736 - 1813)

Definition: Lagrange, Joseph (1736 - 1813): A French mathematician of the eighteenth century. His work Mecanique Analytique (Analytical Mechanics; 1788) was a mathematical masterpiece. It contained clear, symmetrical notation and covered almost every area of pure mathematics. Lagrange developed the calculus of variations, established the theory of differential equations, and provided many new solutions and theorems in number theory. His classic Theorie des fonctions analytiques laid some of the foundations of group theory. Lagrange also invented the method of solving differential equations known as variation of parameters. Show me a picture of Joseph Lagrange !