Editing Integral transform (section)

== History ==
The precursor of the transforms were the [[Fourier series]] to express functions in finite intervals. Later the [[Fourier transform]] was developed to remove the requirement of finite intervals.

Using the Fourier series, just about any practical function of time (the [[voltage]] across the terminals of an [[electronic device]] for example) can be represented as a sum of [[sine]]s and [[cosine]]s, each suitably scaled (multiplied by a constant factor), shifted (advanced or retarded in time) and "squeezed" or "stretched" (increasing or decreasing the frequency). The sines and cosines in the Fourier series are an example of an [[orthonormal basis]].