Fourier, (Jean Baptiste) Joseph (1768-1830)

French applied mathematician whose formulation of heat flow in 1807 contains the proposal that, with certain constraints, any mathematical function can be represented by trigonometrical series. This principle forms the basis of Fourier analysis, used today in many different fields of physics. His idea, not immediately well received, gained currency and is embodied in his Théorie analytique de la chaleur/The Analytical Theory of Heat (1822).

Light, sound, and other wavelike forms of energy can be studied using Fourier's method, a developed version of which is now called harmonic analysis.

Fourier was born in Auxerre, Bourgogne. His education was interrupted by the French Revolution. He accompanied Napoleon on his Egyptian campaign 1798-1801, and on his return was appointed prefect of the département of Isère and later of Rhône, from which he resigned in 1815 in political protest. Soon afterwards he obtained a post at the Bureau of Statistics.

Fourier laid the groundwork for the later development of dimensional analysis and linear programming. He also investigated probability theory and the theory of errors.