Finding Eigenvalues with the Determinant Method

In summary, the conversation is about finding the eigenvalues and eigenvectors of a given matrix using the determinant method. The person asking the question made a mistake and only obtained one eigenvalue instead of the expected two. They then clarified their method and the other person pointed out their mistake. The issue was resolved with thanks.
  • #1
cscott
782
1

Homework Statement



I need the eigenvalues and eigenvectors of [[0,0,1][0,2,0][1,0,0]]

The Attempt at a Solution



How come when I use the determinent method to get the eigenvalues I only end up with 2? Did I make a mistake or is there some other way I'm supposed to find -1, +1?
 
Physics news on Phys.org
  • #2
If you mean what I think you mean, then you must have made a mistake. Can you show your work?
 
  • #3
I used the cofactor expansion along the first row, like on wikipedia so the first two terms are zero and then for the last term: (1)det{ [[0, L-2][1, 0]] } = (0*0) - ((2-L)(1) => L-2 = 0 => L = 2
 
  • #4
If you are expanding along the first row, there are two nonvanishing cofactors. There's an L in the first column and a 1 in the last.
 
  • #5
Oops. Alright thanks.
 

What are eigenvalues of an operator?

Eigenvalues of an operator are the values that, when a linear transformation is applied to them, result in the original vector being scaled by a constant factor. They represent the possible values that can be obtained by the operator when acting on a vector.

How are eigenvalues of an operator calculated?

To calculate the eigenvalues of an operator, we must first find the characteristic polynomial of the operator. This polynomial is then solved to find the roots, which are the eigenvalues of the operator. This process can be done algebraically or numerically.

Why are eigenvalues important in mathematics?

Eigenvalues have many important applications in mathematics, including in linear algebra, differential equations, and quantum mechanics. They can be used to determine the stability of a system, find the optimal solution to a problem, and understand the behavior of physical systems.

Can an operator have more than one eigenvalue?

Yes, an operator can have multiple eigenvalues. In fact, most operators have multiple eigenvalues, with each eigenvalue corresponding to a different eigenvector. The number of eigenvalues an operator has is equal to its dimension.

What is the significance of the eigenvector associated with an eigenvalue?

The eigenvector associated with an eigenvalue is the vector that is scaled by the operator when the eigenvalue is applied. This eigenvector represents the direction or axis of transformation for the operator and can provide important information about the behavior of the system under the operator's action.

Similar threads

  • Advanced Physics Homework Help
Replies
17
Views
1K
  • Advanced Physics Homework Help
Replies
9
Views
1K
  • Advanced Physics Homework Help
Replies
14
Views
1K
  • Quantum Physics
Replies
2
Views
965
Replies
1
Views
1K
  • Advanced Physics Homework Help
Replies
1
Views
1K
  • Advanced Physics Homework Help
Replies
0
Views
228
  • Advanced Physics Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
333
  • Advanced Physics Homework Help
Replies
1
Views
1K
Back
Top