Similarity of Diagonalizable Matrices

  • Thread starter flybynight
  • Start date
  • Tags
    Matrices
In summary, A and B are similar because they can be transformed into the same diagonal matrix D using similarity matrices. To find an invertible matrix P such that P-1AP=B, we can use the eigenvectors of A to build P and then use the similarity transformation to get B. This shows that A and B represent the same linear transformation.
  • #1
flybynight
14
0

Homework Statement


A = {{2,1,0}{0,-2,1}{0,0,1}} and B = {{3,2,-5}{1,2,-1}{2,2,-4}}
Show that A and B are similar by showing that they are similar to the same diagonal matrix. Then find an invertible matrix P such that P-1AP=B

Homework Equations


P-1AP=B, or AP=PB

The Attempt at a Solution


I found the eigenvalues of both matrices to be 2, -2 and 1. I have created the matrix D={{2,0,0}{0,-2,0}{0,0,1}}. But I don't know where to go from there. Any help would be greatly appreciated.
 
Physics news on Phys.org
  • #2
flybynight said:

Homework Statement


A = {{2,1,0}{0,-2,1}{0,0,1}} and B = {{3,2,-5}{1,2,-1}{2,2,-4}}
Show that A and B are similar by showing that they are similar to the same diagonal matrix. Then find an invertible matrix P such that P-1AP=B

Homework Equations


P-1AP=B, or AP=PB

The Attempt at a Solution


I found the eigenvalues of both matrices to be 2, -2 and 1. I have created the matrix D={{2,0,0}{0,-2,0}{0,0,1}}. But I don't know where to go from there. Any help would be greatly appreciated.

Do you know how to diagonalize A itself, in other words how to build P using the eigenvectors of A to get P-1AP=D?
 
  • #3
Yes, I know how to diagonalize the matrices.
 
  • #4
Do you know how similarity matrices work? What linear transformation do they represent?
 
  • #5
flybynight said:
Yes, I know how to diagonalize the matrices.

Well, if you can make P-1AP = D and Q-1BQ = D what is the relationship between A and B?
 

FAQ: Similarity of Diagonalizable Matrices

What is the definition of similarity of diagonalizable matrices?

The similarity of diagonalizable matrices refers to the relationship between two matrices where they have the same eigenvalues and eigenvectors, and therefore can be transformed into each other using a change of basis.

How can you determine if two matrices are similar?

To determine if two matrices are similar, you can check if they have the same eigenvalues and eigenvectors. If they do, then they are similar. Additionally, you can calculate the determinant and trace of both matrices and if they are equal, then they are also similar.

3. What are the benefits of diagonalizable matrices?

Diagonalizable matrices have several benefits, including simpler calculations and easier interpretation of data. They also make it easier to find the inverse of a matrix and can be used for solving systems of linear equations.

4. Can non-square matrices be diagonalizable?

No, non-square matrices cannot be diagonalizable because they do not have the same number of rows and columns, which is a requirement for having eigenvalues and eigenvectors.

5. How can the similarity of diagonalizable matrices be applied in real-world scenarios?

The similarity of diagonalizable matrices is useful in many fields, such as physics, engineering, and computer science. It can be used for modeling and predicting the behavior of systems, analyzing data, and solving complex problems efficiently.

Back
Top