$($a$)$ Find the volume of the solid $\backslash ($ S $\backslash )$ formed when $\backslash ($ R $\backslash )$ is rotated about the line $\backslash (\backslash$mathrm$\{$x$\}=3\backslash )$ using the cylindrical shell method

$($b$)$ Set$-$up the integral representing the volume of the solid S formed when R is rotated about the line $\backslash ($ y$=-1\backslash )$ using the circular ring method.