where L is the length of the string, T is its tension, and is its density. Sine
waves are very important in music, they may be considered the expression of
the vibration with a single frequency. Generally the motion of the source of
sound is more complicated and the produced sound waves are a sum of sev-
eral sine waves with dierent frequencies, all occurring at the same moment.
These frequencies are all multiples of the fundamental one . A more datelined
discussion of these topics is given in [4]