$1.($CTFT and Properties$)(20$ pts$)$ Calculate the Fourier transform of each of the following CT signals $($a$)$ x$($t$)=[$e $$t cos$($$0$t$)]$u$($t$)$ where Re$\{$$\}>0($b$)$ x$($t$)=$ P$+$ k$=0$ k $($t $$ kT$)$ where $|$$|<1$