$9\mathrm{.}1-1$ Find the discrete$-$time Fourier series $($DTFS$)$ and sketch their spectra $|D_r|$ and $\frac{?}{{?}_D{?}_r}$ for $0r{N}_0-1$ for the following periodic signal:

$x[n]=4cos2\mathrm{.}4n+2sin3\mathrm{.}2n$

$9\mathrm{.}1-2$ Repeat Prob. $9\mathrm{.}1-1$ for $x[n]=cos2\mathrm{.}2ncos3\mathrm{.}3n.$

$9\mathrm{.}1-3$ Repeat Prob. $9\mathrm{.}1-1$ for $x[n]=2cos3\mathrm{.}2(n-3).$

$9\mathrm{.}1-4$ Determine and sketch the DTFS spectrum $D_r$ of a $7-$periodic signal $x[n]$ that over $0n6$ is given by