Alexis Claude Clairaut

Alexis Claude Clairaut , 1713-65, French mathematician. He assisted P. L. M. de Maupertuis in measuring (1736) a degree of an arc of a meridian in Lapland. He is noted for his work on differential equations and on curves and for formulating Clairaut's theorem dealing with geodesic lines on the surface of an ellipsoid.

Clairaut, AlexisClaude (1713–65)Frenchmathematician and physicist. In 1736 he took part in an expedition to Lapland to measure the length of a degree of latitude; the result proved that the Earth is an oblate spheroid. The next year he provided a rigorous theoretical explanation for the aberration of starlight, which J.Bradley had been unable to do. He used his own solution of the three-body problem to derive an accurate prediction for the date of perihelion passage of Halley's Comet on its return in 1758/9.