Thread: Eigenvector help

Ok. I have used matlab to help with finding the eignvectors for a given matrix. I have got the eigenvalues already.

the problem Im having is I have got this matrix as the result of doing row operations
ans =
1 0 -1
0 1 1
0 0 0
Now, can I jut read off the diagoinal for the eigenvectors or do I have to solve the equations below

X + 0y –z = 0
0 +y +z = 0
0 + 0 +0 = 0
Thanks

Originally Posted by chuckienz

Now, can I jut read off the diagoinal for the eigenvectors

Never heard of that before.

Originally Posted by chuckienz

or do I have to solve the equations below

X + 0y –z = 0
0 +y +z = 0
0 + 0 +0 = 0
Thanks

Yep, that's correct. That would work.

I think the only time the Eigenvalues are on the diagonal is when you have Diagonalized the matrix. ... Then the matrix is just an n by n with eigenvalues on the diagonal.

Originally Posted by chuckienz

Ok. I have used matlab to help with finding the eignvectors for a given matrix. I have got the eigenvalues already.

the problem Im having is I have got this matrix as the result of doing row operations
ans =
1 0 -1
0 1 1
0 0 0
Now, can I jut read off the diagoinal for the eigenvectors or do I have to solve the equations below

X + 0y –z = 0
0 +y +z = 0
0 + 0 +0 = 0
Thanks

Yes, you need to solve the equations. Here, that gives x= z and y= -z so any eigenvector can be written <z, -z, z>= z<1, -1, 1>. No, you cannot just "read off" the eigenvectors.