P $8\mathrm{.}3-9$ The circuit shown in Figure P $8\mathrm{.}3-9$ is at steady state before the switch closes at time t $0.$ The input to the circuit is the voltage of the voltage source, $24$ V$.$ The output of this circuit, the voltage across the $3-$V resistor, is given by vo$$ t $63$e$0$:$35$t V when t $>0$