**(January 25, 1736 – April 10, 1813) **

This Italo-Franco prime mover was born and baptized as Giuseppe Lodovico Lagrangia in Turin, Italy. But the French version of his name is more widely used. Like some of his scientific predecessors, Joseph-Louis Lagrange pursued a career in law before developing interest in mathematics. And despite being largely self-taught, his proficiency enabled him to be appointed a lecturer in 1755: aged 19 years old. His expertise includes Number Theory, Analysis and Mechanics. He was so brilliant and improvising that Leonhard Euler (his former professor) and Jean le Rond d’Alembert (his mentor) recommended him to succeed Euler as the math director of the Berlin Academy of Sciences, when Euler left for Saint Petersburg in 1766. Lagrange would spend the next 20 years in Berlin: producing fantastic works on both maths and mathematical physics. He returned to France in 1787, joined the Paris Academy of Sciences; and in the following year, published his highly influential masterpiece, titled:

*Mécanique Analytique*, which he had written while in Berlin. It helped transform both classical and celestial mechanics. His other treatises, which were widely praised, included the

*Theorie des Fonctions Analytiques*. Afterwards, he became a math professor at the École Polytechnique Paris, when it was established in 1794. Within Mathematical Analysis, Lagrange researched extensively into the Calculus of Variations, and in the process, invented the Variation of Parameters. He also devised ways of using Differential Calculus to solve problems pertaining to Theory of Probabilities. Of all the established mathematicians of the 18th century, only Leonhard Euler was greater than Lagrange.

I’m a fan of Lagrange. He did many important stuffs in many areas. His Calculus of Variations worked really well for me.

Thanks for the terrific post

Dear Sir,

My name is Vladimir Pletser. I would like to use in a publication about rational mechanics the picture of Joseph-Louis Lagrange that is on the Sapaviva website under the Nr 32.

Would you be so kind to let me know your conditions for using this picture?

Thanking you in adavnce,

with best regards

Vladimir Pletser

Prof. Dr. Ir. V. Pletser

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He was a fantastic mathematician.