Chapter 12, Problem 12.74P

A loop gain function is given by
$T(f)=\frac{\beta \left({10}^3\right)}{\left(1+j\frac{f}{{10}^4}\right)\left(1+j\frac{f}{5\times {10}^4}\right)\left(1+j\frac{f}{{10}^5}\right)}$

Sketch the Nyquist plot for: (a) $\beta =0.005,$ and (b) $\beta =\mathrm{0.05.}$ (c) Is the system stable or unstable in each case?