Multiple choice

A certain system has transfer function G (s) = $\dfrac{s+8}{s^2+\alpha s-4}$ where$\alpha$ is a parameter. Consider the standard negative unity feedback configuration as shown below:

Which of the following statements is true?

  1. The closed loop systems is never stable for any value of $\alpha$.
  2. For some positive value of $\alpha$, the closed loop system is stable, but not for all positive values.
  3. For all positive values of $\alpha$, the closed loop system is stable.
  4. The closed loop system is stable for all values of $\alpha$, both positive and negative.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation