## Joseph Lagrange Biography – Mathematician and astronomer

The** Joseph Lagrange Biography** tells of his contributions in the fields of analysis and number theory to classical and celestial mechanics. He was called the greatest mathematician of the 18th century.

### The Early Years

Joseph Louis Lagrange was born Giuseppe Lodovico Lagrangia on January 25, 1736 in Turin, Italy. His father, Giuseppe Francesco Lodovico Lagrangia, was of Italian and French descent. His mother, Teresa Grosso, was the only daughter of a medical doctor from Cambiano near Turin. Lagrange was the oldest of 11 children, but only 2 lived to adulthood. Even though his father was the Treasurer of the Office of Public Works and Fortifications, they were not rich. His father lost his money due to financial speculations.

### Mathematics

According to the Joseph Lagrange Biography, Lagrange later was quoted as saying, If I had been rich, I probably would not have devoted myself to mathematics. Lagrange went to the College of Turin, but it wasn’t until he read a paper by Edmund Halley that he developed an interest in mathematics. He was basically self taught and at the age of 18 wrote his first paper on mathematics. By the age of 20 he was a professor of geometry in the royal artillery school in Turin. By his mid twenties he was known as the greatest living mathematician. Lagrange also created the calculus of variations. The Joseph Lagrange Biography continues with him going on to become the director of mathematics at the Prussian Academy of Sciences in Berlin. Above all he changed Newtonian mechanics into a branch of analysis and it is now called Lagrangian mechanics.During his years in Prussia, Lagrange married his Vittoria Conti. This union was not a happy one and according to Lagrange’s wishes had no children. His wife died shortly after their marriage.

### Astronomy

In 1764 Lagrange studied the three-body problem of the Earth, Sun and Moon and in 1766 the satellites of Jupiter. In 1772 he found the special-case solution to the problem. It is now known as Lagrangian points. Also in 1764 he began work on why the same side of the Moon always faced Earth. In 1780 he formally proved his solution with the idea of generalized equations of motion.According to the Joseph Lagrange Biography he wrote numerous papers on the problems of astronomy. The most important being:

- 1773, the attraction of ellipsoids
- 1774, the motion of the nodes of a planet
- 1778 & 1783, the method of determining the orbit of a comet

### Later Years

In 1786, according to the Joseph Lagrange Biography, he migrated to Paris. He was given the title of senator and also became a count in the first empire of France. He became a member of the French Academy of Sciences. It was while in France that he met and married his second wife, Renee-Francoise-Adelaide Le Monnie, the daughter of one his colleagues. In 1808 Napoleon made Lagrange a Grand Officer of the Legion of Honour and a Comte (count) of the empire. A week before his death in Paris, he was awarded the Grand Croix of the Order Imperial de la Reunion.It is believe that the frequent bouts of melancholy contributed to his death. On April 10, 1813, Lagrange passed away in Paris France. He was later buried in the Pantheon in Paris.In his honor a street in Paris is named rue Lagrange. In Turin the street where he was born is named via Lagrange.

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