Compute the convolution sum of the following pairs of sequences:

(a) \(x(n)=\left\{\begin{array}{ll}1, & 0 \leq n \leq 4 \\ 0, & \text { otherwise }\end{array} \quad\right.\) and \(\quad h(n)= \begin{cases}a^{n}, & 0 \leq n \leq 7 \\ 0, & \text { otherwise }\end{cases}\)

(b) \(x(n)=\left\{\begin{array}{ll}1, & 0 \leq n \leq 2 \\ 0, & 3 \leq n \leq 6 \\ 1, & 7 \leq n \leq 8 \\ 0, & \text { otherwise }\end{array} \quad\right.\) and \(\quad h(n)= \begin{cases}n, & 1 \leq n \leq 4 \\ 0, & \text { otherwise }\end{cases}\)

(c) \(x(n)=\left\{\begin{array}{ll}a(n), & n \text { even } \\ 0, & n \text { odd }\end{array} \quad\right.\) and \(\quad h(n)= \begin{cases}\frac{1}{2}, & n=-1 \\ 1, & n=0 \\ \frac{1}{2}, & n=1 \\ 0, & \text { otherwise. }\end{cases}\)

Check the results of item (b) using the MATLAB function conv.