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Johann Rahn (Latinised form Rhonius) (10 March 1622 – 25 May 1676) was a Swiss mathematician who is credited with the first use of the division sign, ÷ (a repurposed obelus variant) and the therefore sign, ∴. The symbols were used in ''Teutsche Algebra'', published in 1659. John Pell collaborated with Rahn in this book, which contains an example of the Pell equation. It is uncertain whether Rahn or Pell was responsible for introducing the symbols.
Teutsche Algebra
- Johann H. Rahn
Johann Rahn (Latinised form Rhonius) (10 March 1622 – 25 May 1676) was a Swiss mathematician who is credited with the first use of the division sign, ÷ (a repurposed obelus variant) and the therefore sign, ∴. The symbols were used in ''Teutsche Algebra'', published in 1659. John Pell collaborated with Rahn in this book, which contains an example of the Pell equation. It is uncertain whether Rahn or Pell was responsible for introducing the symbols.
Books
Teutsche Algebra
- Johann H. Rahn
Literature
*R. Acampora ''Johann Heinrich Rahn und seine Teutsche Algebra'', in R. Gebhardt (Herausgeber) ''Visier- und Rechenbücher der frühen Neuzeit'', Schriften des Adam-Ries-Bundes Annaberg-Buchholz 19, 2008, S. 163–178 * Moritz Cantor: Rahn, Johann Heinrich . In: General German Biography (ADB). Volume 27, Duncker & Humblot, Leipzig, 1888, pp. 174 f *Noel Malcolm, Jacqueline Stedall ''John Pell (1611–1685) and His Correspondence with Sir Charles Cavendish: The Mental World of an Early Modern Mathematician'', Oxford University Press, Oxford, 2005 * Christoph Scriba ''John Pell's English Edition of J. H. Rahn 's Teutsche Algebra'', in: R. S. Cohen (Herausgeber) ''For Dirk Struik'', Reidel: Dordrecht 1974, S. 261–274 * Jacqueline Stedall ''A Discourse Concerning Algebra: English Algebra to 1685'', Oxford University Press, Oxford, 2002See also
* History of mathematical notationReferences
;general *Cajori, Florian
Florian Cajori (February 28, 1859 – August 14 or 15, 1930) was a Swiss-American historian of mathematics.
Biography
Florian Cajori was born in Zillis, Switzerland, as the son of Georg Cajori and Catherine Camenisch. He attended schools first ...
. ''A History of Mathematical Notations''. 2 volumes. Lasalle, Illinois: The Open Court Publishing Co., 1928–1929 vol. 2, page 211.
;citations