1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Diagonalization of a matrix

  1. Dec 1, 2015 #1
    1. The problem statement, all variables and given/known data

    Diagonalize matrix a.gif using only row/column switching; multiplying row/column by a scalar; adding a row/column, multiplied by some polynomial, to another row/column.

    2. Relevant equations

    3. The attempt at a solution

    After diagonalization I get a diagonal matrix that looks like this diag.gif . What's the easiest way to tell if the answer is correct/incorrect?
  2. jcsd
  3. Dec 2, 2015 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    One way to tell is to build up the matrices A and B that represent the transformations that you preform in the diagonalisation process. If you've done that then you just need to perform the matrix multiplication ADB where D is the diagonal matrix, and check that it's equal to the original matrix M.

    If the diagonal matrix is of eigenvalues (I can't recall whether they will be for general diagonalisation), another way might be to check that the characteristic equation of M is ##(\lambda-1)^2(\lambda-(x^5+x^4-1))##.
  4. Dec 2, 2015 #3
    Wolfram suggests these eigenvalues eigen.jpg . I must have made some mistakes then.
  5. Dec 3, 2015 #4

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Show us the actual steps you took; that way we can check if you have made any errors.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted