'''Fourier series''' express a piecewise continuous, bounded, periodic function as a linear combination of [[orthogonal]] [[sine]] and [[cosine]] functions. The seeds of the modern theory were developed by [[Joseph Fourier]]. | '''Fourier series''' express a piecewise continuous, bounded, periodic function as a linear combination of [[orthogonal]] [[sine]] and [[cosine]] functions. The seeds of the modern theory were developed by [[Joseph Fourier]]. |