(Solved):   3. A feedback control system is shown in the following figure. The process transfer functi ...

 

3. A feedback control system is shown in the following figure. The process transfer functions are: \[ G(s)=\frac{K(s+40)}{s(s+10)} ; H(s)=\frac{1}{(s+20)} \] (a) Determine the limiting valued of gain \( \mathrm{K} \) for a stable system using Routh-Hurwitz criterion. (b) For the gain that results in marginal stability, determine the magnitude of the imaginary roots.