Find Eigenvalues & Eigenspace for (3,0) (8,-1) Matrix | Homework Statement

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Homework Help Overview

The discussion revolves around finding the eigenvalues and eigenspace of a given 2x2 matrix, specifically the matrix with entries (3,0) and (8,-1). Participants are exploring the computation of eigenvalues and the corresponding eigenspaces.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to compute the eigenspace for the eigenvalue λ = -1 but expresses confusion regarding the results, suggesting a span of t[0,0]. Other participants ask for clarification on the computations and provide their own attempts, including reducing the matrix to row echelon form and questioning the correctness of the identity matrix result.

Discussion Status

Participants are actively engaging with each other's computations and questioning the methods used to find the eigenspace. There is a mix of agreement on the eigenvalues, but confusion remains regarding the eigenspace calculations, indicating a productive exploration of the topic.

Contextual Notes

Some participants mention specific equations and methods used to find eigenvectors, while others highlight discrepancies in the results obtained, suggesting a need for further clarification on the process of solving (A - λI)x = 0.

Chewybakas
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Homework Statement


Find the eigenvalues and eigenspace of the given vector.

Homework Equations


Matrix = (3,0)
(8,-1)

The Attempt at a Solution


I have determined the eigenvalues to be -1 and 3, but when I try compute the eigenspace when lambda = -1 I constantly get confused and end up with the space equal to span(t[0,0]) tεℝ. Can anyone help or confirm that answer!
 
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I agree with the eigenvalues. Can you show your computations for the eigenspace for ##\lambda = -1##?
 
Chewybakas said:

Homework Statement


Find the eigenvalues and eigenspace of the given vector.


Homework Equations


Matrix = (3,0)
(8,-1)


The Attempt at a Solution


I have determined the eigenvalues to be -1 and 3, but when I try compute the eigenspace when lambda = -1 I constantly get confused and end up with the space equal to span(t[0,0]) tεℝ. Can anyone help or confirm that answer!

What are the equations you get when you try to find the eigenvectors for λ = -1?
 
I reduced the original matrix to reduced row echelon form which gave me the identity 2x2 matrix, which when finding two values v1,v2 where when multiplied by the identity matrix gives zero, I get the answer stated above but when i tried a different way I get the eigenspace 2v1 and 9v1 which again confuses me.
 
Chewybakas said:
I reduced the original matrix to reduced row echelon form which gave me the identity 2x2 matrix, which when finding two values v1,v2 where when multiplied by the identity matrix gives zero, I get the answer stated above but when i tried a different way I get the eigenspace 2v1 and 9v1 which again confuses me.

That's not how it works.

For λ = -1, you are solving the equation (A - λI)x = 0
For this eigenvalue, A - λI is
$$ \begin{bmatrix} 4 & 0 \\ 8 & 0\end{bmatrix}$$

When you row reduce this you DON'T get the identity matrix.
 

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