How do we know that the omega is equal to 2pi/19?

[spark360z]

According to the question below, both sine and cosine are component of the signal.

My question is how do we know that the omega is equal to 2pi/19, I mean how to calculate that?

What is a theory behind this? I can calculate the omega if there's only one function but this one has two.

Please help!

**broken link removed**

 

[gadly]

Re: Periodic signal question

You need to ask yourself what Omega means. It is not simply the angular frequency in the sin / cos term. The overall function x[n] is periodic, as implied by the N=19, so you can come up with the fundamental angular frequency corresponding to this period, and it is 2*pi/19.