For a circuit, the current is given by I(t) = 2e-2(t - 3) u(t - 3) A and the voltage is given by V(t) = 2δ(t - 3) V + 4e-2(t - 3) u(t - 3) V for t > 0. The circuit elements are connected in series and consist of:

An ideal voltage source having a voltage value equal to 10 cos(10t + 20°) u(t) drives the series combination of R = 3 Ω and C = 140 F. The natural response of the circuit for t > 0 is proportional to:

A circuit consists of a parallel combination of a resistor R and a capacitor C. This combination is connected in series with another resistor R. What is the overall equivalent time constant of this network?