For the two-port network shown below, the short-circuit admittance parameter matrix is

In the circuit shown, the switch S is open for a long time and is closed at t=0. The current i(t) for t ≥ 0⁺ is

The trigonometric Fourier series for the waveform f(t) shown below contains

Given f(t) = $${L^{ - 1}}\left[ {{{3s + 1} \over {{s^3} + 4{s^2} + \left( {K - 3} \right)s}}} \right].$$ If $$\matrix{ {Lim\,f\,\left( t \right) = 1,} \cr {t \to \infty } \cr } \,\,$$ then the value of K is