7.23 Compute the N-point DFTs of the signals
(a) x(n) = \delta(n)
(b) x(n) = \delta(n - n_0), \quad 0 < n_0 < N
(c) x(n) = a^n, \quad 0 \le n \le N - 1
(d) x(n) = \begin{cases} 1, & 0 \le n \le N/2 - 1 \\ 0, & N/2 \le n \le N - 1 \end{cases} (N \text{ even})
(e) x(n) = e^{j(2\pi/N)k_0n}, \quad 0 \le n \le N - 1
(f) x(n) = \cos\frac{2\pi}{N}k_0n, \quad 0 \le n \le N - 1
(g) x(n) = \sin\frac{2n}{N}k_0n, \quad 0 \le n \le N - 1
(h) x(n) = \begin{cases} 1, & n \text{ even} \\ 0, & n \text{ odd}, \end{cases} \quad 0 \le n \le N - 1