Consider the system shown in Fig. 6.97.
(a) Construct an inverse Nyquist plot of [Y(jω)/E(jω)] –1 . (See Appendix W6.)
(b) Show how the value of K for neutral stability can be read directly from the inverse Nyquist plot.
(c) For K = 4, 2, and 1, determine the gain and phase margins.
(d) Construct a root-locus plot for the system, and identify corresponding points in the two plots. To what damping ratios ζ do the GM and PM of part (c) correspond?