# Mathematician:Joseph Louis Lagrange

## Mathematician

Italian-born French mathematician who made big advances in the fields of the calculus of variations and analytical mechanics.

Contributed to number theory and algebra.

Extended a lot of the fields established by Euler, and in turn laid down the groundwork for later explorations by Gauss and Abel.

Played a leading part in establishing the metric system of weights and measures.

He did the following:

## Nationality

Italian-born, of mixed Italian and French parentage, living mainly in France and Prussia.

## History

• Born: 25 January 1736, Turin, Italy
• 1755: Appointed Professor at Royal Artillery School at Turin
• 1766: Moved to Berlin to take over position of Euler, who had moved to St. Petersburg
• 1786: Moved to Paris after death of Frederick the Great
• Died: 10 April 1813, Paris, France

## Theorems and Definitions

• Lagrange's Theorem (Group Theory) was named after him, although he did not prove the general form. What he actually proved was that if a polynomial in $n$ variables has its variables permuted in all $n!$ ways, the number of different polynomials that are obtained is always a divisor of $n!$.

Results named for Joseph Louis Lagrange can be found here.

Definitions of concepts named for Joseph Louis Lagrange can be found here.

## Critical View

The "generalized coordinates" of our mechanics of today were conceived and installed by Lagrange, and this was an achievement of unmatchable magnitude.
-- Salomon Bochner

## Also known as

Some sources render his name as Joseph-Louis Lagrange.

He was born Giuseppe Lodovico Lagrangia, or Giuseppe Ludovico de la Grange Tournier.

He is also reported as Giuseppe Luigi Lagrange, and also Giuseppe Luigi Lagrangia.

Some prepend his title Comte.

Some sources give his surname as LaGrange.