Jean-Marie Constant Duhamel was a French mathematician and physicist.

His studies were affected by the troubles of the Napoleonic era. He went on to form his own school École Sainte-Barbe. Duhamel's principle, a method of obtaining solutions to inhomogeneous linear evolution equations, is named after him. He was primarily a mathematician but did studies on the mathematics of heat, mechanics, and acoustics. He also did work in calculus using infinitesimals. Duhamel's theorem for infinitesimals says that the sum of a series of infinitesimals is unchanged by replacing the infinitesimal with its principal part.

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