Finding the Fourier Series of a Cosine Function.

[ProPatto16]

Uart,
The question is posted in bold a few posts back and that is exactly how it appears on the piece of paper I have So yeah there's as lot of assuming it seems

 

[LCKurtz]

I don't think there is much left to be said about this problem. Yes, the statement of the problem leaves lots go be desired. However, given the way it was stated, the natural assumption is that L is a half period, which is the usual notation. And the point of the problem is for the student to learn a couple of things.

1. The function itself is its own finite Fourier Series.
2. That if you calculate the Fourier Coefficients you need to be careful about using identities (in this case because of the situation when n=1).

 

[ProPatto16]

Agreed. I'd just like to thank you all for your input though, much appreciated! (:

 

[uart]

Uart,
The question is posted in bold a few posts back and that is exactly how it appears on the piece of paper I have So yeah there's as lot of assuming it seems

Ok I see it now, thanks.

Given the function f(x) = Acos(∏x/L), determine its Fourier series.

there is nothing else, no domain specified or anything.

That's just a poorly written question. Take the period as whatever you want in that case, using 2L is definitely the easiest.