The polar plot of G(jω) = 1/jω is

The given figure shows a control system. The maximum value of gain for which the system is stable is

If Z is the number of zeros of 1 + G(s) H(s) in the right half s plane. N is the number of clockwise encircle elements of (-1 + jo) point. P is the number of poles of G(s) H(s) in right half s plane. The Nyquist stability criterion can be expressed as

Consider the following expressions which indicate the step or impulse response of an initially relaxed system

1. [5 - 4 e^-2t] u(t)
2. [e^-2t + 5] u(t)
3. d(t) + 8 e^-2t u(t)
4. d(t) + 4 e^-2t u(t)

Those which correspond to the step and impulse response of the same system include

A compensating network has . If it is a phase lag circuit the value of a should be