(Solved): Problem 18: The circuit shown below has been operating for a long time with the switch in position \ ...

Problem 18: The circuit shown below has been operating for a long time with the switch in position \( \mathbf{A} \). At \( \mathrm{t}=0 \), the switch is flipped into position B. Find the time-dependent expression for the voltage across the capacitor, \( \mathrm{v}_{\mathrm{C}}(\mathrm{t}) \).