Fourier Series

This chapter shows how certain waveforms are approximated by a series of cosine and sine functions, called a Fourier Series. The idea was proposed by the French mathematician Joseph Fourier (1768–1830), who claimed that any function of a variable, whether continuous or discontinuous, can be expanded into a series of sines of multiples of the variable. ( https://en.wikipedia.org/wiki/Joseph_Fourier ) Today, this claim has been slightly tempered by mathematicians.