Question $1(12$ points, $6$ points$/$each$)$ Cartesian representation and $({}_n,)$ representation

$($a$)$ Let $p_{\text{I}}=-3+j3,$ find its $({}_n,)-$representation.

$($b$)$ Let $p_3=-4cos(30)+j4sin(45),$ find its $({}_n,)-$representation.