Transfer function of the 1-D box filter
Prove Equation (11.12) for the transfer function of the 1-D box filter. (Hint: there are at least to ways to do this. One is to write the transfer function that it can be seen as a geometric sequence 
(1+q +
+. ..+
) with the sum (
− 1)/(q − 1). The other solution is based on the recursive computation of the box filter given by Eq. (11.15).)