Let $Z(p)$ be a rational p.r.f, and let $k$ be a posit :e constant.
(a) Show that the function
$$
\begin{aligned}
Z_1(p) & =\frac{k Z(p)-p Z(k)}{k Z(p)-p Z(p)} \\
& =\frac{N_1(p)}{D_1(p)}
\end{aligned}
$$
is also p.r.
(b) Show that $N_1$ and $D_1$ bave a common factor $(p-k)$.
(c) Show that $N_1$ and $D_1$ will have a common factor $\left(p^2-k^2\right)$ if $p=k$ is a zero of the even-part of $Z(p)$, i.e. if
$$
\left\{Z(p)+Z_s(p)\right\}_{p=k}=0
$$