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: Finding eigenvalues for JCF

  1. Jan 8, 2012 #1
    1. The problem statement, all variables and given/known data
    Ok I was working with finding Jordan canonical form...
    Here is the matrix I was working on:
    | 1 1 1 |
    |-1 -1 -1 |
    | 1 1 0 |

    I am having problem with finding eigenvalues... below is the attempt to solution
    I was not getting the right answer. So, when I used online calculator to find the eigenvalue it was comletely different from what I got!

    2. The attempt at a solution

    |λ-1 , 1 , 1 |
    |-1 , λ+1 , -1 |
    |1 , 1 , λ |

    So, I got values something λ3 = 4

    The values from online calculator was λ3 = 0

    Please help me in finding how they got eigenvalues all 0.
     
  2. jcsd
  3. Jan 8, 2012 #2
    You can either do det(A - xI) = 0, or det(xI - A) = 0, where A is your matrix and x I used instead of lambda. You chose to go with the second one. but forgot to change the signs of the non-diagonal entries.

    Btw, I think this should go into "Calculus and Beyond". JCF certainly isn't precalculus material :P
     
  4. Jan 8, 2012 #3
    oh sorry for wrong section, I am new to this forum...
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook