P $8\mathrm{.}3-3o+$ The circuit shown in Figure P $8\mathrm{.}3-3$ is at steady state before the switch closes at time $t=0.$ Determine the capacitor voltage $v(t)$ for $t>0.$

Answer: $v(t)=-6+18e^{-6\mathrm{.}67t}V$ for $t>0*****($SUB $3$ohm for a $4$ohm and thr voltage source to $30$V$)******$