# Alexis Clairaut

**Alexis Claude Clairaut** (French pronunciation: [alɛksi klod klɛʁo]; 13 May 1713 – 17 May 1765) was a French mathematician, astronomer, and geophysicist. He was a prominent Newtonian whose work helped to establish the validity of the principles and results that Sir Isaac Newton had outlined in the *Principia* of 1687. Clairaut was one of the key figures in the expedition to Lapland that helped to confirm Newton's theory for the figure of the Earth. In that context, Clairaut worked out a mathematical result now known as "Clairaut's theorem". He also tackled the gravitational three-body problem, being the first to obtain a satisfactory result for the apsidal precession of the Moon's orbit. In mathematics he is also credited with Clairaut's equation and Clairaut's relation.

Alexis Claude Clairaut | |
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Born | [1] Paris | 13 May 1713

Died | 17 May 1765 52) Paris | (aged

Nationality | French |

Known for | Clairaut's theorem Clairaut's theorem on equality of mixed partials Clairaut's equation Clairaut's relation Apsidal precession |

Scientific career | |

Fields | Mathematics |