Lagrange: A Well-Behaved Function

This paper outlines the biography and achievements of Joseph Louis Lagrange (1736-1813) and includes a detailed explanation, with examples, of the Lagrange Multiplier method for optimizing multivariate functions subject to constraint. The Lagrange Multiplier is widely used in chemistry, physics, and economics, in particular. The paper considers the origin of economics' use of the multiplier and provides a concrete example of how it is used in microeconomic theory. While the focus is on the multiplier's application to microeconomics, the intended audience includes all teachers and students who encounter any of Lagrange's contributions. Since Lagrange's contributions to mathematics are numerous, so too are those who might benefit from learning more about the man and his time.