Fourier Series

A Fourier series is a series expansion of a periodic function into a sum of trigonometric functions, making many problems involving the function easier to analyze because trigonometric functions are well understood; Fourier series were first used by Joseph Fourier to find solutions to the heat equation. Well-behaved functions such as smooth functions have Fourier series that converge to the original function, though most functions have infinitely many terms in their Fourier series and the series does not always converge. Fourier series are closely related to the Fourier transform, a more general tool that also finds frequency information for functions that are not periodic. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/