Date: Dec 9, 2012 10:57 AM
Author: emammendes@gmail.com
Subject: Help with RootLocusPlot
Hello all

I am experiencing some problems when using the command RootLocusPlot. Here

is what I need to do

tf[s_,\[Alpha]_,k_]:=k (s+\[Alpha])^3/(s^2-2 s+2)^2;tf[s,\[Alpha],k]

RootLocusPlot[tf[s,2,k],{k,0,20000},PlotRange->{{-12,2},{-8,8}},Method->"NDS

olve",PlotPoints->1000]

First of all, the whole thing takes quite some time to finish, but worse

part is not that, the result gives the false impression that the real Root

Locus is what is shown on the screen. It is not!

M***B takes a second to do the same thing and returns the real thing!

I have changed the number of points, the range of k and etc.

What am I doing wrong? Is there a way of setting specific values of k

(something like logspace in M***B)?

Many thanks

Ed