32. JOSEPH-LOUIS LAGRANGE

(January 25, 1736 – April 10, 1813)

This Italo-Franco prime mover was born and baptized as Giuseppe Lodovico Lagrangia in Turin, Italy. But he later adopted the French version of his name. 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 tutor in 1755: aged 19 years. His expertise includes Number Theory, Analysis and Rational Mechanics. He was so brilliant and improvising that Leonhard Euler (his academic adviser via correspondence) 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: Mécanique Analytique, which he had written while in Berlin. This helped transform both Classical and Celestial mechanics. His other acclaimed treatises include: the Theorie des Fonctions Analytiques and the Résolution des Équations Numériques. At this time, he was a professor at the École Polytechnique Paris, which was established in 1794. Within Analysis, Lagrange researched extensively on Calculus of Variations, and in the process, consolidated the Variation of Parameters. He even devised ways of using Differential Calculus to solve problems pertaining to Theory of Probabilities. Of all the geniuses whose maths shaped the 18th century, only Leonhard Euler surpassed Lagrange.