Understanding the Eigenvalue Problem for a 4x4 Matrix with Rank 1 and Trace 10

In summary, the conversation discusses finding the eigenvalues of a 4x4 matrix A with a rank of 1 and a trace of 10. The person asking the question is confused about how to create the matrix and represent the given fact that dim(im(A)) = 1. They are also looking for tips or pointers on how to approach this problem. The response suggests reviewing the concepts of image and dimension of a matrix and considering any special cases where the eigenvalues may have a simple relation to the trace. It is also suggested to sketch out the matrix by assigning 16 variables.
  • #1
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Homework Statement



Let there be a 4X4 Matrix A with dim(im(A), or rank = 1 , and trace=10. What are the Eigenvalues of A? Are there any multiplicities?

The Attempt at a Solution



While I understand that the trace of a matrix that's 4X4 = the sum of the diagonal elements, I'm confused about how to create this matrix A to find the eigenvalues, and how to represent the given fact that dim(im(A)) = 1.

Any tips/pointers would be helpful!
 
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  • #2
You need to review what is meant by the image and dimension of a matrix: what does rank=1 tell you?
Also - do you know of any special cases where the eigenvalues have some simple relation to the trace?
https://www.physicsforums.com/showthread.php?t=682216

Since it is 4x4 - you can always just assign 16 variables and sketch it out.
Needs lots of paper or a large whiteboard (or window).
 
Last edited:

1. What is an eigenvalue?

An eigenvalue is a characteristic value that represents the scale factor of a linear transformation. It is a special value that does not change direction when a transformation is applied to a vector.

2. What is an eigenvector?

An eigenvector is a vector that does not change direction when a linear transformation is applied to it. It is associated with a specific eigenvalue and represents the direction of the transformation.

3. Why is finding eigenvalues important?

Finding eigenvalues is important because it allows us to understand the behavior of linear transformations and systems of differential equations. It also helps in solving many problems in physics, engineering, and other fields.

4. What is the process for finding eigenvalues?

The process for finding eigenvalues involves solving a characteristic equation, which is obtained by setting the determinant of a matrix to zero. The resulting solutions are the eigenvalues of the matrix.

5. Can all matrices be diagonalized?

No, not all matrices can be diagonalized. Only square matrices with linearly independent eigenvectors can be diagonalized. Matrices with repeated eigenvalues or complex eigenvalues cannot be diagonalized.

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