Jean Frédéric Frenet (; 7 February 1816 – 12 June 1900) was a French

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

, and

meteorologist A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmosphere of Earth, atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists ...

. He was born and died in

Périgueux Périgueux (, ; or ) is a commune in the Dordogne department, in the administrative region of Nouvelle-Aquitaine, southwestern France. Périgueux is the prefecture of Dordogne, and the capital city of Périgord. It is also the seat of ...

, France. He is best known for being an independent co-discoverer of the Frenet–Serret formulas. He wrote six out of the nine formulas, which at that time were not expressed in

vector notation In mathematics and physics, vector notation is a commonly used notation for representing vectors, which may be Euclidean vectors, or more generally, members of a vector space. For denoting a vector, the common typographic convention is lower ...

. These formulas are important in the theory of

space curve In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that ...

s (

differential geometry Differential geometry is a Mathematics, mathematical discipline that studies the geometry of smooth shapes and smooth spaces, otherwise known as smooth manifolds. It uses the techniques of Calculus, single variable calculus, vector calculus, lin ...

), and they were presented in his doctoral thesis at

Toulouse Toulouse (, ; ; ) is a city in southern France, the Prefectures in France, prefecture of the Haute-Garonne department and of the Occitania (administrative region), Occitania region. The city is on the banks of the Garonne, River Garonne, from ...

in 1847. That year he became a professor at Toulouse, and one year later, 1848, he became professor of mathematics at

Lyon Lyon (Franco-Provençal: ''Liyon'') is a city in France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, Switzerland, north ...

. He also was director of an astronomical observatory at Lyon. Four years later, in 1852, he published the Frenet formulas in the ''

Journal de Mathématiques Pures et Appliquées The ''Journal de Mathématiques Pures et Appliquées'' () is a French monthly scientific journal of mathematics, founded in 1836 by Joseph Liouville (editor: 1836–1874). The journal was originally published by Charles Louis Étienne Bachelier. ...

''. In 1856 his

calculus Calculus is the mathematics, mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizations of arithmetic operations. Originally called infinitesimal calculus or "the ...

primer was first published, which ran through seven editions, the last one published posthumously in 1917.

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* * {{DEFAULTSORT:Frenet, Jean Frederic People from Périgueux 1816 births 1900 deaths 19th-century French mathematicians École Normale Supérieure alumni 19th-century French astronomers 19th-century French writers French male writers 19th-century French male writers