The forward path transfer functions of unity feedback control systems are given below.

{a) G(s) _ K(s + 4) - s(s2 + 4s + 4)(s + 5)(s + 6)

{b) K G(s) = s(s+2)(s'+5)(s+10)

{c) G(s) _ K(s2 + 2s + 10)

- s(s + 5)(s + 10)

{d) G(s) - K(s2 + 4)

- (s + 2)2(s + 5)(s + 6)

Construct the root loci for K :2: 0 .