Take the 2-minute tour ×
Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.

I have a polynomial equation of the fourth order, which has $4$ roots depending on a variable parameter s1. For each s1 I have $4$ solutions. I need a LinePlot of all roots to see how they move in the complex plane when the parameter s1 changes. I can solve my equation but I don't know how to plot all the roots together on one diagram (points connected with line for each solution).

poly = -6.110000000000001`*^6 k^4 + 1000.` s1^2 + 60.335263000000005`(-5.` k + s1)^2;

Table[ NSolve[ poly == 0, k], {s1, {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9}}]
share|improve this question
    
    
You have already asked quite similar question and I think you've seen e.g. this Factoring a two variable polynomial in a special way, in fact, this answers your question. –  Artes Mar 31 at 22:31
    
I don't understand light and dark green and lines there while roots moving –  Pipe Mar 31 at 23:14

1 Answer 1

up vote 5 down vote accepted

You can use RootLocusPlot.

poly = -6.110000000000001`*^6 k^4 + 1000.` s1^2 + 60.335263000000005` (-5.` k + s1)^2;

RootLocusPlot[1/poly, {s1, 0, 1}, FeedbackType -> None, 
PoleZeroMarkers -> {"ParameterValues" -> Range[0.1, 0.9, 0.1]}]

enter image description here

share|improve this answer
    
Thank you Suba Thomas. This is it. –  Pipe Apr 1 at 16:20
    
Glad it solved your problem. –  Suba Thomas Apr 1 at 16:37

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.