Given $$f\left( z \right) = {1 \over {z + 1}} - {2 \over {z + 3}}.$$ If $$C$$ is a counterclockwise path in the $$z$$-plane such that
$$\left| {z + 1} \right| = 1,$$ the value of $${1 \over {2\,\pi \,j}}\oint\limits_c {f\left( z \right)dz} $$ is

The impedance looking into nodes 1 and 2 in the given circuit is

In the circuit shown below, current through the inductor is

If V_A - V_B = 6 V then V_C - V_D is