- Alexis Clairaut
Infobox Scientist

name = Alexis Claude de Clairault

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caption = Alexis Claude de Clairault

birth_date =May 7 ,1713

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death_date =May 17 ,1765

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nationality = French

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field =mathematics

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known_for =Clairaut's equation

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footnotes =**Alexis Claude de Clairault**(or**Clairaut**) (May 3 ,1713 –May 17 ,1765 ) was a Frenchmathematician andintellectual .**Biography****Childhood**Clairault was born in

Paris, France , where his father taughtmathematics . He was a prodigy — at the age of twelve he wrote a memoir on four geometrical curves and under his father's tuition he made such rapid progress in the subject that in his thirteenth year he read before theAcadémie française an account of the properties of four curves which he had discovered. When only sixteen he finished a treatise on tortuous curves, "Recherches sur les courbes a double courbure", which, on its publication in 1731, procured his admission into theFrench Academy of Sciences , although he was below the legal age as he was only eighteen.**Expeditions**In 1736, together with

Pierre Louis Maupertuis , he took part in the expedition to Lapland, which was undertaken for the purpose of estimating a degree of the meridian, and on his return he published his treatise "Théorie de la figure de la terre" (1743). In this work he promulgated the theorem, known asClairaut's theorem , which connects thegravity at points on the surface of a rotatingellipsoid with the compression and the centrifugal force at theequator .In 1741 Clairault went on a scientific expedition to measure the length of a meridian degree on the

Earth 's surface, and on his return in 1743 he published his "Théorie de la figure de la terre". This hydrostatical approach to predicting the shape of the earth is founded on a paper byColin Maclaurin , which had shown that a mass of fluid set in rotation about a line through itscentre of mass would, under the mutual attraction of its particles, take the form of aspheroid . This work of Clairault treated ofheterogeneous spheroids and contains the proof of his formula for the accelerating effect of gravity in a place of latitude. In 1849 Stokes showed that the same result was true whatever was the interior constitution or density of the Earth, provided the surface was a spheroid of equilibrium of small ellipticity.**Focus on astronomical motion**He obtained an ingenious approximate solution of the problem of the three bodies; in 1750 he gained the prize of the St Petersburg Academy for his essay "Théorie de la lune"; and in 1759 he calculated the

perihelion of Halley's comet.The "Théorie de la lune" is strictly Newtonian in character. This contains the explanation of the motion of the

apsis which had previously puzzled astronomers, and which Clairaut had at first deemed so inexplicable that he was on the point of publishing a new hypothesis as to the law of attraction when it occurred to him to carry the approximation to the third order, and he thereupon found that the result was in accordance with the observations. This was followed in 1754 by some lunar tables. Clairaut subsequently wrote various papers on theorbit of theMoon , and on the motion ofcomet s as affected by the perturbation of the planets, particularly on the path of Halley's comet.**Personal life and death**His growing popularity in society hindered his scientific work: "He was focused," says Bossut, "with dining and with evenings, coupled with a lively taste for women, and seeking to make his pleasures into his day to day work, he lost rest, health, and finally life at the age of fifty-two."

Clairaut died in Paris in 1765.

**References*** Grier, David Alan, " [

*http://www.pupress.princeton.edu/titles/7999.html When Computers Were Human*] ",Princeton University Press , 2005. ISBN 0-691-09157-9.

* Casey, J., "Clairaut's Hydrostatics: A Study in Contrast," American Journal of Physics, Vol. 60, 1992, pp. 549-554.**ee also***

Clairaut's equation

*Clairaut's theorem

*Human computer **External links*** [

*http://www.clairaut.com Chronologie de la vie de Clairaut (1713-1765)*]

*

* [*http://www.maths.tcd.ie/pub/HistMath/People/Clairaut/RouseBall/RB_Clairaut.html W.W. Rouse Ball "A Short Account of the History of Mathematics"*]

*Wikimedia Foundation.
2010.*

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**Alexis Clairaut**— Alexis Claude Clairaut Alexis Clairaut Portrait gravé de Clairaut par Charles Nicolas Cochin fils et Louis Jacques Cathelin, d après un dessin de Carmontelle … Wikipédia en Français**Alexis Clairaut**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 7. Mai 1713 in Paris, † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers. Bereits… … Deutsch Wikipedia**Alexis Claude Clairaut**— Alexis Clairaut Portrait gravé de Clairaut par Charles Nicolas Cochin fils et Louis Jacques Cathelin, d après un dessin de Carmontelle. Naissance 13 mai 1713 Paris (France) Décès … Wikipédia en Français**Clairaut's equation**— In mathematics, a Clairaut s equation is a differential equation of the form To solve such an equation, we differentiate with respect to x, yielding so Hence, either … Wikipedia**Alexis Claude Clairaut**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 7. Mai 1713 in Paris, † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers. Bereits… … Deutsch Wikipedia**Alexis-Claude Clairault**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 7. Mai 1713 in Paris, † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers. Bereits… … Deutsch Wikipedia**Alexis Clairault**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 7. Mai 1713 in Paris, † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers. Bereits… … Deutsch Wikipedia**Clairaut**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 7. Mai 1713 in Paris, † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers. Bereits… … Deutsch Wikipedia**Alexis-Claude Clairaut**— Alexis Claude Clairaut; Portrait Alexis Claude Clairaut (auch Clairault) (* 3. Mai 1713 in Paris; † 17. Mai 1765 in Paris) war ein französischer Mathematiker, Geodät und Physiker. Er war das zweite von 21 Kindern eines Mathematiklehrers … Deutsch Wikipedia**Clairaut**— may refer to: Alexis Claude Clairaut, a French mathematician Clairaut (crater), a crater on The Moon Or to the work of Alexis Claude Clairaut: Clairaut s theorem Clairaut s equation This disambiguation page lists articles associated with the s … Wikipedia