Discrete Fourier Transform

ankh

1. The problem statement, all variables and given/known data
Find the discrete Fourier transform X[k] = DFTn {x[n]} of the following
periodic sequences x[n] = x[n - N] with period N:

(a) For n = 0 . . .N - 1 we have x[n] =[tex]\delta[/tex][n].
(b) For n = 0 . . .N - 1 we have x[n] = [tex]\mu[/tex][n] -[tex]\mu[/tex][n - K] with K < N.
(c) x[n] = cos( (2*pi*M*n)/N ).

2. Relevant equations
We dont have a book for my digital processing class and i missed couple of classes so i have no idea how to start these problems. A little hint or a link to a good tutorial/source would be greatly appreciated.


3. The attempt at a solution

Redbelly98

Wikipedia has good info:

http://en.wikipedia.org/wiki/Discret...orm#Definition