Sketch the Nyquist plot for each of the following specifications of G(s)H(s), and use th...

Sketch the Nyquist plot for each of the following specifications of G(s)H(s), and use the continuous-time Nyquist criterion to determine the range of values of K (if any such range exists) for which the closed-loop system is stable. Note: In sketching the Nyquist plots, you may find it useful to sketch the corresponding Bode plots first. It also is helpful to determine the values of or for which G(jω)H(jω) is real