1. Joseph Louis Lagrange By Daniel Tovbin and Wenjun Ouyang of 701

2. Life of Joseph Louis Lagrange • Joseph Louis Lagrange was born on January 25, 1736 in Turin, Sardinia. • Lagrange died on April 10, 1813 in Paris, France. He was 77 years old when he died. • He was influenced by the work of a Halley’s 1693’s work on the use of algebra and optics. • Lagrange was 1 of 11 children. • He was married to Renée-Françoise-Adélaide Le Monnie.

3. Education and Career Joseph Louis Lagrange was educated at the college of Turin. He was then offered to work in the Berlin Academy. He was a founding member of the Royal Academy of Science of Turin.

4. Accomplishments What was Joseph Louis Lagrange famous for? • Lagrange was one of the creators of the calculus of variations, which is a field of mathematics that deals with a functional. • He also invented the method of solving differential equations. • He proved that every natural number is the sum of four squares, which is now known as Lagrange’s four square theorem.

5. More Accomplishments • Lagrange solved the resulting system of the n+1 differential equations. • He applied his methods to the study of Jupiter’s and Saturn’s orbit. • He also reduced the equations of the quadrics into their canonical forms.

6. Awards and Prizes Lagrange was awarded the Grand Croix Ordre Imperial de la Reunion. He was awarded the 1764 prize of the French Academy of Sciences for his memoir on the libration of the Moon. He won the 1772 prize on the three body problem with Euler. He had won the 1774 prize for finding about the motion of the moon. He also had won the 1780 prize on perturbations of the orbits of comets by the planets.

7. Interesting Facts: Some interesting facts about Joseph Louis Lagrange are: • Lagrange had worked for Fredrick II of Berlin for 20 years. • In his appearance, Lagrange was medium height with pale blue eyes and a colorless complexion. In character, he was nervous and timid, he detested controversy, and he allowed others to take credit for things he has done himself.

8. More Interesting Facts: • In 1810, Joseph Louis Lagrange was only able to complete two-thirds of the Méchanique analytique before his death. • Lagrange published 2 volumes of his calculus lectures. • Lagrange’s nervous system was put on too much pressure and the doctors said that they would not be responsible for certain illnesses. They recommended for him to rest. In 1813, he died in Paris, France.

9. Picture of the mathematician: Joseph Louis Lagrange

10. Pictures of Inventions: • 3 = 12 + 12 + 12 + 02 • 31 = 52 + 22 + 12 + 12 • 310 = 172 + 42 + 22 + 12. Calculus Of Variations Equation An example of the four square theorem.