$7.(10$ points$)$ Sketch $\backslash ($ v$($t$)\backslash )$ to scale

$($a$)$ Before and after the switch is opened, assuming the circuit was in steady$-$state with switch closed at time $\backslash (0^\{-\}\backslash )$

$($b$)$ Repeat for a switch that is initial opened and closes at time $\backslash ($ t$=0\backslash )$