C. L. Lehmus

Daniel Christian Ludolph Lehmus ( born July 3, 1780 in Soest, † January 18, 1863 in Berlin) was a mathematician who is best known for the eponymous set of Steiner Lehmus today.

Life

Lehmus was a grandson of the poet Johann Adam Lehmus (1707-1788) and the Berlin physician Emilie Lehmus (1841-1932) was his great-niece. His father Christian Balthasar Lehmus, who was a scientist and director of high school in Soest, led even the entire school education of his son. After training by his father studied Lehmus 1799-1802 in Jena and Erlangen and then went to Berlin in 1803. There he gave private lectures on mathematics and in 1811 received his doctorate. From December 18th 1813 to Easter 1815, he was temporarily working as a lecturer at the University of Berlin. In 1814 he then took a position as teacher of mathematics and natural sciences at the main mine -Eleven Institute and in 1826 he was also also teacher at the Royal United Artillery and Engineering School. At this given the title of professor was conferred in 1827 and 1836, he was awarded the Red Eagle, Fourth Class. Besides his work at these two schools he held until 1837 also lectures at the University.

Work

Lehmus wrote a series of mathematical textbooks, among them be multiply again aufgelegtes textbook on geometry. This provides a particularly simple solution to the problem of Ottajano. In his book, application of higher Calculs on geometrical and mechanical, especially ballistic tasks, he examined the first German mathematician the properties of strophoid, a special plane curve. Lehmus has written numerous articles for magazines and mathematics was represented with a contribution including in the first edition of Crelle Journal ( 1826). In the Nouvelles Annales de Mathématiques he published an elegant solution to the trigonometric Malfattischen problem. Due to a printing error, which has been partially also adopted by other later publications, but is there under the name Lechmütz.

In 1840 Lehmus wrote a letter to the Swiss mathematician Charles -François Sturm, in which he formulated the now named after him and asked for a set of elementary geometric proof of his statement. Storm handed the request to colleagues and one of the first evidence was provided by Jakob Steiner. 1850 published Ludolph Lehmus then well its own proof of the theorem.

Works (selection)

  • Tasks from the body teaching. Berlin / Halle 1811
  • Textbook of arithmetic numbers, letters arithmetic and algebra. Leipzig 1816
  • Textbook of applied mathematics. Volume I -III, Berlin 1818, 1822 ( online copy of Volume I ( Google) )
  • Theory of curved pin. Berlin 1818
  • The first most basic concepts and teachings of the higher analysis and Curve teaching. Berlin 1819
  • Uebungsaufgaben to the doctrine of the greatest and least. Berlin 1823 ( online copy ( Google) )
  • Textbook of geometry. Berlin 1826
  • Collection of resolved tasks from the field of applied mathematics. Berlin 1828
  • Basic teachings of higher mathematics and the mechanical sciences. Berlin 1831
  • Application of higher Calculs geometric and mechanical, especially ballistic tasks. Leipzig 1836
  • Short Guide for the Lecture of higher analysis, higher geometry and analytical mechanics. Duncker and Humblot 1842 ( online copy ( Google) )
  • Algebraic tasks from the whole field of pure mathematics with an indication of the results. Duncker and Humblot, Berlin 1846 ( online copy ( Google) )
  • Limit provisions in comparisons of circles, which are dependent on the same triangle, both among themselves and with the triangle itself C. Geibel, Leipzig 1851 ( online copy ( Google) )
Steiner–Lehmus theorem Plane (geometry) Allgemeine Deutsche Biographie Integrated Authority File
533016
de