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: Eigenvalues of operator

  1. Nov 11, 2007 #1
    1. The problem statement, all variables and given/known data

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

    3. 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?
  2. jcsd
  3. Nov 11, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If you mean what I think you mean, then you must have made a mistake. Can you show your work?
  4. Nov 11, 2007 #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
  5. Nov 11, 2007 #4


    User Avatar
    Science Advisor
    Homework Helper

    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.
  6. Nov 11, 2007 #5
    Oops. Alright thanks.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook