Write the equations in cylindrical coordinates.

$($a$)$

$4$x$29$x $+4$y$2+$ z$2=3$

$4$r$2$cos$2($$)+4$r$29$rcos$($$)+$z$2=3$

$($b$)$

z $=9$x$29$y$2$

z$=9$r$2$cos$(2$$)$