Physics teacher: both light and sound waves are subject to superposition.
This means that when considering what the total wave "looks" like, it might not always be a nice sinusoidal shape. For instance, when combining a wave with another wave twice its frequency, (a note plus its octave; deep red light and very violet light) the resultant wave approaches a sawtooth wave.
Also, although Wikipedia is not 100% reliable, it is a superb source. It is attended to by numerous experts, and typically explains topics excellently.

This question is for testing whether you are a human visitor and to prevent automated spam submissions.