Desargues , Girard
(1591–1661) French mathematician and engineer
Little is known of the early life of Desargues except that he was born in Lyons in France. He did serve as an engineer at the siege of La Rochelle (1628) and later became a technical adviser to Cardinal de Richelieu and the French government. He is said to have known René Descartes.
Around 1630 Desargues joined a group of mathematicians in Paris and concentrated on geometry. In his most famous work,Brouillon projet d'une atteinte aux événements des rencontres d'une cône avec un plan (1639; Proposed Draft of an Attempt to deal with the Events of the Meeting of a Cone with a Plane), he applied projective geometry to conic sections. Desargues' theorem states that if the corresponding points of two triangles in nonparallel planes in space are joined by three lines that intersect at a single point, then the pairs of lines that are the extensions of corresponding sides will each intersect on the same line. Blaise Pascal was greatly influenced by Desargues, whose contribution to projective geometry was not recognized until a handwritten copy of his work was found in 1845. This oversight probably arose because he used obscure botanical symbols instead of the better-known Cartesian symbolism.

Scientists. . 2011.

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  • Desargues, Girard — ▪ French mathematician born February 21, 1591, Lyon, France died October 1661, France       French mathematician who figures prominently in the history of projective geometry. Desargues s work was well known by his contemporaries, but half a… …   Universalium

  • Girard Desargues — Naissance 21 février 1591 Lyon (France) Décès Octobre 1661 Lyon (France) Nationalité Française Champs …   Wikipédia en Français

  • Girard — may refer to:PlacesIn the United States: *Girard, Alabama *Girard, Georgia *Girard, Illinois *Girard, Kansas *Girard, Michigan *Girard, Minnesota *Girard, Ohio *Girard, Pennsylvania *Girard, Texas *Girard Township, Macoupin County, Illinois… …   Wikipedia

  • Desargues —   [de zarg], Gérard oder Girard, französischer Mathematiker, getauft Lyon 2. 3. 1591, ✝ ebenda 8. 10. 1662; zuerst Offizier, später Baumeister und Kriegsingenieur; war technischer Berater Richelieus und der französischen Regierung; mit R.… …   Universal-Lexikon

  • Desargues's theorem — Geom. the theorem that if two triangles are so related that the lines joining corresponding vertices meet in a point, then the extended corresponding lines of the two triangles meet in three points, all on the same line. [named after G.… …   Universalium

  • Desargues — biographical name Gérard or Girard 1591 1661 French mathematician …   New Collegiate Dictionary

  • Gérard Desargues — Girard Desargues Girard Desargues Naissance 2 mars 1591 Lyon (France) Décès Octobre 1661 Lyon (France) …   Wikipédia en Français

  • Gérard Desargues — Girard Desargues Girard Desargues (February 21 1591–October 1661) was a French mathematician and engineer, who is considered one of the founders of projective geometry. Desargues theorem, the Desargues graph, and the crater Desargues on the Moon… …   Wikipedia

  • Théorème de Desargues — dans un plan projectif : les deux triangles (non plats) ABC et A B C ont leurs sommets sur 3 droites distinctes p = (AA ) , q = (BB ) et r = (CC ) ; alors ces 3 droites sont concourantes (en S) si et seulement si les points P = (BC) ∩… …   Wikipédia en Français

  • Gérard Desargues — (* 21. Februar 1591 in Lyon; † Oktober 1661 in Lyon) war ein französischer Architekt und Mathematiker, der als einer der Begründer der Projektiven Geometrie gilt …   Deutsch Wikipedia

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