A feedback control system is shown in the figure.
The maximum allowable value of \( n \) such that the output \( y(t) \), due to any step disturbance signal \( d(t) \), becomes zero at steady-state, is ________ (in integer).
The plant in the feedback control system shown in the figure is \( P(s) = \frac{a}{s^2 - b^2} \), where \( a > 0 \) and \( b > 0 \). The type(s) of controller \( C(s) \) that CANNOT stabilize the plant is/are
Consider the control system block diagram given in Figure (a). The loop transfer function $G(s)H(s)$ does not have any pole on the $j\omega$-axis. The counterclockwise contour with infinite radius, as shown in Figure (b), encircles two poles of $G(s)H(s)$. Choose the correct statement from the following options for closed loop stability of the system.
