JosephLouis Lagrange
JosephLouis de Lagrange (born January 25, 1736 in Turin as Giuseppe Lodovico Lagrangia , † April 10, 1813 in Paris ) was an Italian mathematician and astronomer .
Lagrange founded the analytical mechanics ( Lagrange formalism with the Lagrange function), which he presented in 1788 in his famous textbook Mécanique analytique . Further areas of work were the threebody problem of celestial mechanics ( Lagrange points ), the calculus of variations and the theory of complex functions . He made contributions to group theory (before it existed as a separate branch of research) and to the theory of quadratic forms in number theory . In analysis the Lagrangian representation of the remainder of the Taylor formula and in the theory of differential equations the Lagrange multiplier rule is known.
Life
Lagrange was born as Giuseppe Ludovico Lagrangia. His father was a welltodo civil servant of French descent, but speculation caused the family to suffer significant financial losses. Lagrange attended the Turin college, where he showed his first interest in mathematics at the age of seventeen, after stumbling across a publication by Edmund Halley . His father wanted him to be a lawyer, but at school Lagrange ended up becoming more interested in math , especially geometry . Within a year he acquired all the knowledge of a fully trained mathematician of his time.
At the age of 19 he received a chair in mathematics at the Royal Artillery School in Turin . Here he published his first scientific work on differential equations and the calculus of variations . In 1757 he was one of the founders of the Turin Academy .
Following the call of Frederick II of Prussia , Lagrange went to Berlin in 1766 as the successor to Leonhard Euler as director of the Royal Prussian Academy of Sciences , of which he had been a member since 1756 . Here he dealt with problems of astronomy , but also with partial differential equations and questions from geometry and algebra .
After the death of Frederick II in 1786, he went to Paris in 1787 as a pensioner of the Académie des Sciences , of which he had been a member since 1772. After a phase of depression, his wellknown work on theoretical physics Mécanique analytique appeared here in 1788 ; another publication deals with the threebody problem of celestial mechanics.
In 1793, during the French Revolution, the reign of terror began and all foreigners were banished from France. However, Lagrange received an exemption. From 1795 he taught for a short time at the École Normale Supérieure and entered the newly founded Institut de France . From 1797 he taught at the École polytechnique . In 1776 he became an honorary member of the Russian Academy of Sciences in St. Petersburg , in 1791 a fellow of the Royal Society and in 1790 a fellow and in 1813 an honorary member of the Royal Society of Edinburgh . In 1801 he was elected a foreign member of the Göttingen Academy of Sciences . Since 1808 he was a foreign member of the Bavarian Academy of Sciences .
Under Napoleon I he was appointed Count and Senator of France. Thereby he met the father of AugustinLouis Cauchy and became a supporter of Cauchy.
Lagrange is laid out in the Panthéon . It is especially at the Eiffel Tower immortalized .
The lunar crater Lagrange and the asteroid (1006) Lagrangea are named after him.
See also
 Lagrange's theorem
 interpolation
 Lagrangian density
 Lagrange formalism
 Lagrange multiplier
 Lagrange polynomial
 Lagrange point
 Lagrange resolvent
 Four squares set
Fonts
 Théorie Des Fonctions Analytiques, Contenant Les Principes Du Calcul Différentiel, Dégagés De Toute Considération D'Infiniment Petits ou d'Évanouissans, De limites Ou de Fluxions, Et Réduits A L'Analyse Algébrique Des Quantités Finies. Paris: Imprimerie de la République, Prairial an V, Paris 1797.
 Lagrange's Mathematical Elementary Lectures. German separate edition by H. Niedermüller, Teubner, Leipzig 1880.

Mécanique Analytique. Desaint, Paris 1788; 2nd edition in 2 volumes, Courcier, Paris 1811–1815.
 also Oeuvres , Vol. 11, 12
 German translation by Friedrich Murhard: Analytical Mechanics. Vandenhoeck and Ruprecht, Göttingen 1797, the translation of the 4th edition by H. Servus was published by J. Springer in 1887.
 Oeuvres. GauthierVillars, Paris 1867–1892, editors Joseph Serret , Gaston Darboux , Ludovic Lalanne, 14 volumes, SUB Göttingen , Gallica .
literature
 O. Stamfort: Lagrange. In: Hans Wussing , W. Arnold (Ed.): Biographies of important mathematicians. Berlin 1983.
 Diedrich Herrmann: Joseph Louis Lagrange (1736–1813) , BerlinTreptow, Archenbold Observatory 1963 (21 pages).
 Jean Itard: Lagrange, Joseph Louis . In: Charles Coulston Gillispie (Ed.): Dictionary of Scientific Biography . tape 7 : Iamblichus  Karl Landsteiner . Charles Scribner's Sons, New York 1973, p. 559573 . .
 W. Barroso Filho: La mécanique de Lagrange, Principes et méthodes. Paris 1994.
 MT Borgato, L. Pepe: Lagrange: Appunti per una biografia scientifica. Turin 1990.
 KarlEugen Kurrer : The History of the Theory of Structures. Searching for Equilibrium. Ernst & Sohn , 2018, p. 30ff, 808f and p. 1020 (biography), ISBN 9783433032299 .
 Lagrange. In: R. Flood, R. Wilson: The Great Mathematicians. Arcturus, London 2012, ISBN 9781848588431 , pp. 201204.
Web links
 Literature by and about JosephLouis Lagrange in the catalog of the German National Library
 Entry in the mathematician family tree
 John J. O'Connor, Edmund F. Robertson : JosephLouis Lagrange. In: MacTutor History of Mathematics archive .
Individual evidence
 ^ Historical members of the academy: JosephLouis Comte de Lagrange. BerlinBrandenbrgische Akademie der Wissenschaften, accessed on December 29, 2019 .
 ^ Foreign members of the Russian Academy of Sciences since 1724: Lagrange, Joseph Louis de, Graf. Russian Academy of Sciences, accessed December 29, 2019 (in Russian).
 ↑ entry on Lagrange; Joseph Louis (1736–1813) in the Archives of the Royal Society , London
 ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed December 29, 2019 .
 ^ Holger Krahnke: The members of the Academy of Sciences in Göttingen 17512001. (= Treatises of the Academy of Sciences in Göttingen, PhilologicalHistorical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, MathematicalPhysical Class. Volume 3, Vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3525825161 , p. 143.
personal data  

SURNAME  Lagrange, JosephLouis 
ALTERNATIVE NAMES  Lagrange, JosephLouis de; Lagrangia, Giuseppe Lodovico 
BRIEF DESCRIPTION  Italian mathematician and astronomer 
DATE OF BIRTH  January 25, 1736 
PLACE OF BIRTH  Turin , Italy 
DATE OF DEATH  April 10, 1813 
Place of death  Paris , France 