computing eigenvalues- Is it a bug?

[Kleofáš Slavný]

Hi all,

I am trying to compute eigenvalues of matrix [[2,3,-2],[1,4,-2],[2,10,-5]] (matrix is from Engineering Mathematics by K.A. Stroud and Dexter J. Booth, 7th edition, page 510, exercise 48).

The eigenvalues are 1, 1, -1. Computing on TI-Nspire CX CAS and TI-89 Titanium led to "Error: Non-real result" which is evidently wrong. So I switched the TI-Nspire from real to rectangular mode and I obtained results 1+3,27615e^-8*i,  1-3,27615e^-8*i, -1. I do not understand why the results are complex numbers although the characteristic equation is -(1+x)*(1-x)^2=0

Is it a bug in OS or not?

Mathcad 15, Mathcad Prime 3, Casio Classpad, HP-50g are giving the correct results.

Thanks for your responses

[Abdullah Ford]

Not a bug. Just find the eigenvalue of the TRANSPOSE of your matrix and you'll get the book's answer.

--
--
To post to this group, send email to tins...@googlegroups.com
To unsubscribe send email to tinspire+u...@googlegroups.com
For more options, visit this group at
http://groups.google.com.au/group/tinspire?hl=en-GB?hl=en-GB
The tns documents shared by group members are archived at
https://sites.google.com/site/tinspiregroup/classroom-news/welcome-abouttime

---
You received this message because you are subscribed to the Google Groups "tinspire" group.
To unsubscribe from this group and stop receiving emails from it, send an email to tinspire+u...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Kleofáš Slavný]

Thanks, it is OK now.

Personally, I feel this behavior strange.

Dne neděle, 7. září 2014 11:13:56 UTC+2 PyramidPower napsal(a):

[Wayne Pace]

You may also like to try the eigenvalue routines that are incorporated in the CX CAS Library named linalgcas.  These often performs better than the native routines in the CX CAS Catalog and the library is installed automatically on new systems.

 

Wayne

[Kleofáš Slavný]

Thanks for the tip, I will try it.

K.

Dne neděle, 7. září 2014 18:42:33 UTC+2 Wayne napsal(a):