Nikolai Ivanovich Lobachevsky
From Academic Kids

Nikolay_Ivanovich_Lobachevsky.jpeg
Nikolai Ivanovich Lobachevsky (Никола́й Ива́нович Лобаче́вский) (December 1 1792  February 24 1856) was a Russian mathematician.
Contents 
Biography
Lobachevsky was born in Nizhny Novgorod, Russia. His parents were Ivan Maksimovich Lobachevsky, a clerk in a landsurveying office, and Praskovia Alexandrovna Lobachevskaya. In 1800, his father died and his mother moved to Kazan. In Kazan, Nikolai Ivanovich Lobachevsky attended Kazan Gymnasium, graduating in 1807 and then Kazan University which was founded just three years earlier, in 1804.
At Kazan University, Lobachevsky was influenced by professor Martin Bartels (1769  1833), a friend of Carl Friedrich Gauss. Lobachevsky received a Master's degree in physics and mathematics in 1811. In 1814, he became a lecturer at Kazan University and in 1822 he became a full professor. He served in many administrative positions and was the rector of Kazan University from 1827 to 1846. He retired (or was dismissed) in 1846, after which his health rapidly deteriorated.
In 1832, he married Varvara Alexivna Moisieva. They had seven children.
Mathematical results
Lobachevsky's main achievement is the development (independently from János Bolyai) of nonEuclidean geometry. Before him, the mathematicians were trying to deduce Euclid's fifth postulate from other axioms. He would instead develop a geometry in which the fifth postulate was not true. This idea was first reported on February 23 (Feb. 11, O.S. ), 1826 to the session of the department of physics and mathematics, and this research was printed in the Bulletin of Kazan University (Вестник Казанского университета) in 18291830. The recognition of his ideas by the mathematical community was quite slow. They were fully accepted only several decades after Lobachevsky's death.
Another of Lobachevsky's achievements was developing a method for the numerical approximation of the roots of algebraic equations. This method is now known as DandelinGräffe method, named after two other mathematicians who discovered it independently. In Russia, it is called Lobachevsky method. Lobachevsky gave the definition of a function as a correspondence between two sets of real numbers (Dirichlet gave the same definition independently soon after Lobachevsky).
In popular culture
In the 1950s, humorist, satirist (and mathematician) Tom Lehrer wrote a song, inspired by a Danny Kaye routine about Stanislavsky, in which he credited Lobachevsky with teaching him the secret of success as a mathematician: plagiarism ("But remember always to call it please, 'research'.") Lehrer has noted that he chose Lobachevsky mainly because his name was reminiscent of Stanislavsky's, and not because Lobachevsky is particularly known for this misdemeanor.
In Poul Anderson's novella "Operation Changeling" (F&SF, 1969; Operation Chaos, 1971), a group of sorcerers navigate a nonEuclidean universe with the assistance of the ghosts of Lobachevsky and Bolyai. (The novella also makes a reference to Lehrer's song.)
External link
eo:Nikolaj LOBAĈEVSKIJ fr:Nicolaï Ivanovitch Lobatchevsky he:ניקולאי איוונוביץ' לובצ'בסקי nl:Nikolaj Ivanovitsj Lobatsjevski ja:ニコライ・イワノビッチ・ロバチェフスキー pl:Mikołaj Łobaczewski pt:Nikolai Ivanovich Lobachevsky ru:Лобачевский, Николай Иванович sv:Nikolaj Ivanovitj Lobatjevskij tt:Nikolay Lobaçevski