Understanding Eigen Vectors and Diagonalization for a 2x2 Matrix

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Discussion Overview

The discussion revolves around finding eigenvalues and eigenvectors for a specific 2x2 matrix, as well as the process of diagonalization. Participants explore the compatibility of equations derived from eigenvalues and discuss methods for solving the associated problems.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents a 2x2 matrix and reports eigenvalues of 30.77 and 9.22, expressing confusion over the resulting equations for eigenvectors.
  • Another participant suggests correcting the eigenvalue to 9.23 and emphasizes the need to find the nullspace of the matrix to determine the eigenspace.
  • A different participant points out that the two equations derived from the eigenvalues are not compatible due to rounding errors and notes that they are essentially the same when using ratios.
  • One participant advises using fractions instead of decimals for clarity in calculations.
  • The original poster acknowledges understanding the relationship between the variables in the equations and mentions a need to diagonalize the matrix and sketch a contour, seeking additional resources.

Areas of Agreement / Disagreement

Participants express differing views on the rounding of eigenvalues and the compatibility of the resulting equations. There is no consensus on the best approach to proceed with the calculations, and the discussion remains unresolved regarding the optimal method for finding eigenvectors.

Contextual Notes

Participants have noted potential limitations related to rounding errors and the choice of using decimals versus fractions in calculations. There is also mention of normalization conditions for eigenvectors.

Who May Find This Useful

Students studying linear algebra, particularly those focusing on eigenvalues, eigenvectors, and matrix diagonalization, may find this discussion relevant.

koolrizi
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I am trying to find eigen values and eigen vectors for A
Its 2X2 matrix. A first row (16 -10) second row (-10 24)
I got Eigen values as 30.77 and 9.22 but when i try to find eigen vectors here are the equations I end up with
-14.77v1 - 10v2= 0
-10v1 - 6.77v2 = 0

Kinda confused how to proceed with this.

Thanks
 
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Use 9.23, you rounded wrong.

The procedure for finding associated eigenvectors is to find the nullspace of A-λI. So you have to solve the nullspace of that matrix you wrote up to find the 30.77-eigenspace. Then you'll need to do the process again for 9.23.

Does this clear things up for you? Or do you need help with solving the nullspace? Because that should be easy.
 
these two equations are not compatible, because you have rounded your eigenvalues, but if you would have used the ratios as an eigenvalued, you'd see that these thwo equations are exactly the same.

When you are solveing for eigenvectors you have to use either of these equation, because they are same, and then if your states are normalizabe, you have to normalize it.

v1^2+v2^2=1

that's your second equation in system!
 
(You should use fractions instead of decimals)

You've spent the whole semester solving problems like that, haven't you? So what's the trouble?
 
Got it

Thanks I got that part. I didnt realize that v1=-0.677v2 for both equations. I am actually taking a different course which uses linear algebra but its been a while since i studied it. Now I have to diagonalize the matrix and also sketch the unit standard deviation contour. If you know any good sites for that do let me know.

Thanks everyone
 

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