# Composite sine functions

1. Apr 21, 2012

### Cluelessness

Hey all!
I have a question concerning the addition of 2 sine functions.
Could anyone point me to the right direction as to what happens to the period and frequency when two sine functions are added together?
Note: when adding, these two functions possess two different frequencies.

2. Apr 21, 2012

### DonAntonio

I know what period of a trigonometric function is, but I can't say the same of "frequency" though

this seems to be a term from physics related to the inverse of the function's argument times $2\pi$ ...

Anyway, we have the trigonometric identity $\sin x+\sin y=2\sin \frac{x+y}{2}\cos\frac{x-y}{2}$ .

DonAntonio

3. Apr 21, 2012

### Cluelessness

Thanks DonAntonio :D
But do you happen to know any other relationships apart from Simpsons' or Werner's?
My dilemma is, given a graph, how would you figure out what it is made up of? i.e what sine functions were added to produce that graph?
I just need a hint - do you happen to know any thing else which could help me?

4. Apr 21, 2012