# LEONHARD EULER

1995/08/01
Azkune Mendia, Iñaki - Elhuyar Fundazioa
**Iturria:**
Elhuyar aldizkaria

Swiss mathematician born in Basel on 15 April 1707. He learned mathematics from his father. He was sent to Basel to study theology. There he had as professor Jacques I Bernouilli, a Swiss sage, who was the same teacher as his father, when he became a great friend of his children. These went to St. Petersburg (Russia) in 1732, at the request of the Russian empress Catherine I, and brought Euler with them. There he began to work in the chair of mathematics.

In 1735, a brain congestion caused him to lose sight of an eye. The following year *he wrote the Complete Treatise on* Mechanics. There he applied mathematical analysis to the science of movement. In 1741, Frederick II traveled to Berlin invited by the king of Denmark and Norway to give some strength to the Academy of Sciences. At that time *he wrote the* Theory of Isoperimeters. This theory allowed to determine curves.

Along *with this book, he wrote the Theory of the Movement of Comets and Planets and the Theory of Magnetization,* solving the problems of ballistics to the king of Prussia. Years later he wrote two other books: *Introduction to Infinitesimal Calculus* (1748) *and Differential Calculus Institutions* (1755).

In 1766 he returned to St. Petersburg. That same year he lost his sight of good eye. But Euler did not stop working. Between 1768 and 1770 appears *the book Institutions* of Integral Calculation.

His mathematics applied it to astronomy, obtaining the nature of some disturbances. That is why he pioneered the theories of Euler, Laplace and Lagrange. His greatest work was the theory of the Moon, that is, the analysis of the concrete motion of the Moon. Despite the fact that the results were not correct, progress was considerable. He also noted that light was a waveform and that color depended on wavelength. A century later, these statements were confirmed by the British scientist Young.

He died in St. Petersburg on 18 September 1783 for a stroke attack.