So do you know how to perform a root locus calculation?

 

Yes. I do. But, the four answers are wrong.

 

are you sure about that? Did you find your poles and breakaway point, asymptote centroid?

 

Yes. I do. But, the four answers are wrong.

Why do you say that? But just in case you are right, why dont you post your root locus plot and we can take a look. I got a result that looks much like one of the four but i'd like to see yours first.

 

I agree with MrAl, I too have found a plot that looks correct.

 

asymptote centroid is the breakaway point right?

 

I sketched the root locus
The poles are 0, -2 and -5.
n=3, m=0.
asymptote angles 60, -60 and 180
asymptote centroid -7/3.

 

You're almost there... you may want to mark your branches. centroids are not same as breakaway. You have calculated centroid, now you need the breakaway.

 

How to find the breakaway

 

did you mark your branches? So, your breakaway has to been between two open loop poles (remember this rule)? Marking branches help you check your work.

 

Yeah the breakaway point is not correct in your sketch.