Ludolph Lehmus

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Daniel Christian Ludolph Lehmus (born July 3, 1780 in Soest ; † January 18, 1863 in Berlin ) was a mathematician who is best known today for the Steiner-Lehmus theorem named after him .

Life

Lehmus was a grandson of the poet Johann Adam Lehmus (1707–1788) and the Berlin doctor Emilie Lehmus (1841–1932) was his great niece. His father Christian Balthasar Lehmus, who was a scientist and director of a grammar school in Soest, himself directed the entire school education of his son. After training by his father, Lehmus studied in Jena and Erlangen from 1799 to 1802 and then went to Berlin in 1803. There he gave private lectures on mathematics and received his doctorate in 1811. From December 18, 1813 to Easter 1815, he worked temporarily as a private lecturer at the University of Berlin . In 1814 he then took a position as a teacher of mathematics and natural sciences at the Hauptbergwerks-Eleven-Institut and from 1826 he also became a teacher at the United Royal Artillery and Engineering School . At this he was awarded the title of professor in 1827 and in 1836 he received the Red Eagle Order, fourth class. In addition to his work at these two educational institutions, he also held lectures at the university until 1837.

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Lehmus wrote a number of mathematical textbooks, including his repeatedly reprinted textbook on geometry . This contains a particularly simple solution to the Ottajano's task . In his book Application of the Higher Calculus to Geometric and Mechanical, especially Ballistic Problems , he was the first German mathematician to investigate the properties of strophoids , a special flat curve . Lehmus wrote numerous articles for mathematics journals and was represented in the first edition of Crelles Journal (1826) with a contribution. In the Nouvelles Annales de Mathématiques he published an elegant trigonometric solution to the Malfattian problem . However, due to a copying error, which was partially adopted from other later publications, it is listed there under the name Lechmütz .

In 1840 Lehmus wrote a letter to the Swiss mathematician Charles-François Sturm , in which he formulated the sentence that is now named after him and asked for an elementary geometric proof of his statement. Sturm passed the request on to colleagues and one of the first pieces of evidence was provided by Jakob Steiner . In 1850 Ludolph Lehmus published his own proof of the theorem.

Works (selection)

  • Exercises from the body theory . Berlin / Halle 1811
  • Textbook of number arithmetic, letter arithmetic and algebra . Leipzig 1816
  • Applied mathematics textbook . Volume I-III, Berlin 1818, 1822 ( online copy of Volume I (Google) )
  • Theory of the crook . Berlin 1818
  • The first simplest basic concepts and teachings of higher analysis and curve theory . Berlin 1819
  • Exercises for teaching the largest and smallest . Berlin 1823 ( online copy (Google) )
  • Geometry textbook . Berlin 1826
  • Collection of solved problems from the field of applied mathematics . Berlin 1828
  • Basic teachings of higher mathematics and the mechanical sciences . Berlin 1831
  • Application of the higher calculus to geometric and mechanical, especially ballistic, tasks . Leipzig 1836
  • Short guide for lecturing higher analysis, higher geometry and analytical mechanics . Duncker and Humblot 1842 ( online copy (Google) )
  • Algebraic problems from the whole field of pure mathematics with details of the results . Duncker and Humblot, Berlin 1846 ( online copy (Google) )
  • Limit determinations when comparing circles which are dependent on the same triangle, both among themselves and with the triangle itself . C. Geibel, Leipzig 1851 ( online copy (Google) )

literature

Web links

Individual evidence

  1. ^ Wilhelm Koner: Scholarly Berlin in 1845 . T. Scherk, Berlin 1846, p. 209 ( excerpt (Google) )
  2. ^ A b Siegmund Günther :  Lehmus, Daniel Christian Ludolph . In: Allgemeine Deutsche Biographie (ADB). Volume 18, Duncker & Humblot, Leipzig 1883, p. 147 f.
  3. ↑ Diane and Roy Dowling: The Lasting Legacy of Ludolph Lehmus (PDF; 388 kB). In: Manitoba Math Links 2, 3, 2002, pp. 3-4
  4. ↑ Harold Scott MacDonald Coxeter , Samuel L. Greitzer: Geometry Revisited . Mathematical Association of America , Washington 1967, pp. 14-16 ($ 1.5 The Steiner – Lehmus Theorem ).
personal data
SURNAME Lehmus, Ludolph
ALTERNATIVE NAMES Lehmus, Daniel Christian Ludolph (full name)
BRIEF DESCRIPTION German mathematician
DATE OF BIRTH July 3, 1780
PLACE OF BIRTH Soest
DATE OF DEATH January 18, 1863
Place of death Berlin