E6.6 A negative feedback system has a loop transfer function

(a) Find the value of the gain when the z of the closedloop roots is equal to 0.5.

(b) Find the value of K when two roots lie on the imaginary axis. Determine the value of the three roots.

K(s + 5) = L(s) Ge(s)G(s): = s(s - 2)