## What is Joseph-Louis Lagrange known for?

Lagrange invented the method of solving differential equations known as variation of parameters, applied differential calculus to the theory of probabilities and worked on solutions for algebraic equations. He proved that every natural number is a sum of four squares.

What did Joseph-Louis Lagrange do for a living?

Joseph-Louis Lagrange, comte de l’Empire, original Italian Giuseppe Luigi Lagrangia, (born January 25, 1736, Turin, Sardinia-Piedmont [Italy]—died April 10, 1813, Paris, France), Italian French mathematician who made great contributions to number theory and to analytic and celestial mechanics.

### Who invented Lagrange’s Theorem?

In mathematics, Lagrange’s theorem usually refers to any of the following theorems, attributed to Joseph Louis Lagrange: Lagrange’s theorem (group theory) Lagrange’s theorem (number theory) Lagrange’s four-square theorem, which states that every positive integer can be expressed as the sum of four squares of integers.

What did Pierre Simon Laplace discover?

Laplace announced the invariability of planetary mean motions (average angular velocity). This discovery in 1773, the first and most important step in establishing the stability of the solar system, was the most important advance in physical astronomy since Newton.

## Who is a famous female mathematician?

Five Historic Female Mathematicians You Should Know

• Hypatia (ca. 350 or 370 – 415 or 416) (© Bettmann/CORBIS)
• Sophie Germain (1776 – 1831) (Public Domain)