P$-4\mathrm{.}1$ Let x$($t$)=11$cos$(7$t$$$/3).$ In each of the following parts, the discrete$-$time signal x$[$n$]$ is obtained by sampling x$($t$)$at a rate fs samples$/$s$,$ and the resultant x$[$n$]$ can be written as x$[$n$]=$Acos$($ $1$n $+)$ For each part below, determine the values of A$,,$ and $$ $1$ such that $0$ $1$ $.$ In addition, state whether or not the signal has been over$-$sampled or under$-$sampled. $($a$)$ Sampling frequency is fs $=9$ samples$/$s$.($b$)$ Sampling frequency is fs $=6$ samples$/$s$.($c$)$ Sampling frequency is fs $=3$ samples$/$s