A tape recorder has a speed control system so that H(s) = 1 with negative feedback and

Question:

A tape recorder has a speed control system so that H(s) = 1 with negative feedback and
L(s) = Gc(s)G(s) = K / s(s + 2)(s2 + 4s + 5).
(a) Sketch a root locus for K, and show that the dominant roots are s = -0.35 ± j0.80 when K = 6.5.
(b) For the dominant roots of part (a), calculate the settling time and overshoot for a step input.