In the figure shown, the current i (in ampere) is ______.

The z-parameter matrix $$\begin{bmatrix}z_{11}&z_{12}\\z_{21}&z_{22}\end{bmatrix}$$ for the two-port network shown is

Assume that the circuit in the figure has reached the steady state before time t = 0 when the 3 Ω resistor suddenly burns out, resulting in an open circuit. The current i(t) (in ampere) at t = 0⁺ is ____________.

In the $$RLC$$ circuit shown in the figure, the input voltage is given by v_i(t) = 2 cos(200t)+4 sin(500t). The output voltage v₀(t) is