What are Eigenvectors and Eigenvalues?

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Homework Help Overview

The discussion revolves around the concepts of eigenvectors and eigenvalues, particularly in the context of a specific matrix problem. Participants are examining the relationship between eigenvalues, nullspaces, and determinants.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss identifying eigenvalues and the process of finding eigenvectors through nullspace. There are questions about the implications of having a zero eigenvalue and the relationship between determinants and eigenvalues. Some participants express confusion about manipulating matrix equations and the significance of the nullspace.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the eigenvalue problem. Some guidance has been offered regarding the relationship between eigenvalues and determinants, but no consensus has been reached on the specific steps to take next.

Contextual Notes

There are references to specific matrix operations and the potential complexity of the problem, indicating that participants may be working under constraints related to their current coursework and upcoming topics.

flyingpig
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Homework Statement



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The Attempt at a Solution



a) Did it already, 3 is the eigenvalue

b) This is just finding the nullspace and the basis of the nullspace are my eigenvectors right?

c) ignore this one, we cover this next term
 
Last edited by a moderator:
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flyingpig said:

Homework Statement



http://img820.imageshack.us/img820/4874/cah.th.png

Uploaded with ImageShack.us



The Attempt at a Solution



a) Did it already, 3 is the eigenvalue

b) This is just finding the nullspace and the basis of the nullspace are my eigenvectors right?
This is simpler than you seem to be making it out to be. If 0 is an eigenvalue, then det(A) = 0, and Ax = 0x for any eigenvector of 0.
flyingpig said:
c) ignore this one, we cover this next term
 
Last edited by a moderator:
Wait for b)

Ax = λx = 0x = 0

Ax = 0 <=== not nullspace?

Are you implying that

det(Ax) = det(0I) = 0

det(Ax) = 0

How do you pull the x out?
 
flyingpig said:
Wait for b)

Ax = λx = 0x = 0

Ax = 0 <=== not nullspace?

Are you implying that

det(Ax) = det(0I) = 0

det(Ax) = 0

How do you pull the x out?
You can't just move a bunch of symbols around. You need to do something with your matrix A.

[tex]\begin{bmatrix}2&-1&1\\-1&2&1\\1&1&2\end{bmatrix}[/tex]
 
RowReduce...
 

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