Finding the eigenvalues of a 4x4 matrix?

Hi!

I need help finding the eigenvalues of a 4x4 matrix. Been working with the same problem for 2 days now. I just can't solve it. :( Help me pls!

The matrix (A) is:

(Notice that the matrix is symmetric, if that is to any help)

I have come this far (If I'm on the right track).

det = 0

How do I solve for L from this? I would appreciate any help.

Thanks!

/Gordina

Finding eigenvalues of a 4x4 matrix.

I asked this question in the homework forum, but desided to move it here, since I'm not in a hurry.

My problem:

How do I find the eigenvalues of this matrix:

(Notice that it is symmetric, if that helps)

As I understand I need to solve from:

det = 0

The only way I know how to do this is by cofactor expansion. But that would take all day for me. There's got to be a faster way.

galactus said:

" Your matrix should be:

This gives a characteristic polynomial of:

"

Why is galactus using a different matrix, and how did he get it? And how did he get the characteristic polynomial of that matrix?

I've been working on this problem for several days now. I just can't solve it. I would be so happy if anyone could help me.

/Gordina