(Solved): 4. The circuit shown in the figure below is at a steady state before the switch closes at time \( t= ...

4. The circuit shown in the figure below is at a steady state before the switch closes at time \( t=0 \). The input to the circuit is the voltage of the voltage source, 18 V . The output of this circuit is the current across the capacitor, \( \mathrm{v}(t) \). Determine \( v(t) \) for \( t>0 \). ( \( \mathbf{1 5} \) points)