For the circuit shown below, $=42V,R_1=12,R_2=24,R_3=36,$ and $L=4\mathrm{.}0mH.$ Find the values of $I_1$ and $I_2($in A$)$ at the following times. $($Indicate the direction with the signs of your answers.$)$

$($a$)$ immediately after switch S is closed

$I_1=$

$I_2=$

$AA$

$($b$)$ a long time after S is closed

$I_1=$

$I_2=$

A

A

$($c$)$ immediately after S is reopened $($Assume the circuit has reached a steady state before S is reopened.$)$

$I_1=$

$I_2=$

$AA$

$($d$)$ a long time after S is reopened

$I_1=$

$I_2=$