Thomas Clausen (mathematician)
{{short description|Danish mathematician and astronomer (1801–1885)}}{{About other people|the Danish mathematician and astronomer||Thomas Clausen (disambiguation){{!}}Thomas Clausen}}{{Infobox mathematician
| image = Thomas Clausen.jpg
| birth_date = 16 January 1801
| birth_place = Snogbæk, Sottrup Municipality, Duchy of Schleswig
| death_date = 23 May 1885 (aged 84)
| death_place = Tartu, Imperial Russia
| known_for = Clausen function, Clausen's formula
}}
Thomas Clausen (16 January 1801, Snogbæk, Sottrup Municipality, Duchy of Schleswig – 23 May 1885, Tartu, Imperial Russia) was a Danish mathematician and astronomer.
Life
Clausen learned mathematics at home. In 1820, he became a trainee at the Munich Optical Institute and in 1824, at the Altona Observatory after he showed Heinrich Christian Schumacher his paper on calculating longitude by the occultation of stars by the moon.{{cite book |title=The Biographical Encyclopedia of Astronomers |last=Hockey |first=Thomas |year=2009 |publisher=Springer Publishing |isbn=978-0-387-31022-0 |accessdate=August 22, 2012 |url=http://www.springerreference.com/docs/html/chapterdbid/58289.html}} In 1828, he discovered Clausen's formula.{{Cite journal |date=1828-01-01 |title=Ueber die Fälle, wenn die Reihe von der Form y = etc. ein Quadrat von der Form z = etc. hat. |url=http://dx.doi.org/10.1515/crll.1828.3.89 |journal=Journal für die reine und angewandte Mathematik |volume=1828 |issue=3 |pages=89–91 |doi=10.1515/crll.1828.3.89 |issn=0075-4102}} He eventually returned to Munich, where he conceived and published his best known works on mathematics. In 1832, he discovered the Clausen function.{{Cite journal |date=1832-01-01 |title=Über die Function sinφ + sin2φ + sin3φ + etc. |url=http://dx.doi.org/10.1515/crll.1832.8.298 |journal=Journal für die reine und angewandte Mathematik |volume=1832 |issue=8 |pages=298–300 |doi=10.1515/crll.1832.8.298 |issn=0075-4102}} In 1842, Clausen was hired by the staff of the Tartu Observatory, becoming its director in 1866–1872.
Works by Clausen include studies on the stability of Solar System, comet movement, ABC telegraph code and calculation of 250 decimals of pi (later, only 248 were confirmed to be correct). In 1840, he discovered the Von Staudt–Clausen theorem. Also in 1840, he also found two compass and straightedge constructions of lunes with equal area to a square, adding to three (including the lune of Hippocrates) known to the ancient Greek mathematician Hippocrates of Chios; it was later shown that these five lunes are the only possible solutions to this problem.{{citation|title=The problem of squarable lunes|journal=American Mathematical Monthly|volume=107|issue=7|year=2000|pages=645–651|jstor=2589121|first=M. M.|last=Postnikov|authorlink=Mikhail Postnikov|doi=10.2307/2589121}}. Translated from Postnikov's 1963 Russian book on Galois theory. In 1854, he factored the sixth Fermat number as 264+1 = 67280421310721 × 274177.
Notes
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References
- {{Citation | last1=Biermann | first1=Kurt-R. | title=Thomas Clausen: Mathematiker und Astronom | url=http://resolver.sub.uni-goettingen.de/purl?GDZPPN002180928 | mr=0164862 | year=1964 | journal=Journal für die reine und angewandte Mathematik | issn=0075-4102 | volume=216 | pages=159–197| doi=10.1515/crll.1964.216.159 }}
- {{Citation | last1=Lathrop | first1=Carolyn | last2=Stemkoski | first2=Lee | editor1-last=Bradley | editor1-first=Robert E. | editor2-last=D'Antonio | editor2-first=Lawrence A. | editor3-last=Sandifer | editor3-first=C. Edward | title=Euler at 300 | chapter-url=https://www.maa.org/ebusppro/Bookstore/ProductDetail/tabid/170/Default.aspx?ProductId=711 | publisher=Math. Assoc. America | location=Washington, DC | series=MAA Spectrum | isbn=978-0-88385-565-2 | mr=2349552 | year=2007 | chapter=Parallels in the work of Leonhard Euler and Thomas Clausen | pages=217–225}}
- {{MacTutor|id=Clausen|title=Thomas Clausen}}
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Category:19th-century Danish mathematicians
Category:19th-century Danish astronomers
Category:People from the Duchy of Schleswig