Problem 1: 5 points for each step in the root locus method. -5 for missing the break-in and break-out points. -7 for not even computing them.
Problem 2:
Calculation error: -1,2
Routh Array:
initial setup plus the right b1 and b2, 5 points
c1 = 5 points
final answer (0<k<16), 5 points.
Root Locus:
using correct form to calculate: majority of points
Pick point on imaginary axis for stability: 5
Correct calculation: (product of three distances)/10: 10 points.
Problem 3: 10 points for each listed part. For each, 3 for correct computational approach, 3 for correct computations and 4 for correct plot/interpretation.