In the transient circuit the switch is opened at the time t = 0, the expression for the voltage across the capacitor for t > 0 is:
1
\(20 + 15{e^{ - 4t}} + 40{e^{ - t}}\)
2
\(30 + 15{e^{ - 4t}} - 40{e^{ - t}}\)
3
\(30 - 15{e^{ - 4t}} + 40{e^{ - t}}\)
4
\(20 - 15{e^{ - 4t}} + 40{e^{ - t}}\)