In the applet Fourier series
the user may choose the first 21 coefficients of a Fourier series
by means of scroll bars and look at the graph of the resulting function.
The goal is to get some feeling for for the role played by the
individual frequencies in the sum ("superposition").
Some examples illustrate the fact that practically all
interesting (not too pathological)
peroidic functions may be represented as a series of this type.
Since the main goal is to achieve a qualitative understanding,
no detailed numerical information may be gained.
The applet is started from the red button in its own window.