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!

Eigenvalue and matrix

  1. Nov 16, 2009 #1
    1. The problem statement, all variables and given/known data

    Let A =
    a b
    c d
    A characteristic value of A (often called an eigenvalue) is denoted by λ and satisfies the relation

    det(A - λI) = 0

    Obtain the characteristics values of E =
    1 -1
    -1 1


    2. Relevant equations

    Well I is the unit or identity matrix

    1 0
    0 1


    3. The attempt at a solution

    I don't understand how E can be of any relation to what the question is asking. Does E = A?

    det(A - λI) = 0

    => a - λ, b
    c, d - λ = 0

    super. ad + λ² - λa - λd + bc = 0

    Let's presume for a second that their asking me that A = E

    that means a=1, b = -1,c = -1,d = 1

    => 1 + λ² - λ(1-1) + 1 = 0
    =? λ² = -2

    that canny be though can it?

    Any suggestions are welcomed!

    Thanks
    Tom
     
  2. jcsd
  3. Nov 16, 2009 #2

    Mark44

    Staff: Mentor

    Yes, they want the solutions of the equation |E - [itex]\lambda[/itex]I| = 0

    I get different eigenvalues, both real. Check your determinant work.
     
  4. Nov 17, 2009 #3
    ahh, my bad

    x² - 2x = 0

    => x(x-2)

    therefore, x = 0, 2

    Is that what you got?

    Thanks :)
    Tom
     
  5. Nov 17, 2009 #4

    Mark44

    Staff: Mentor

    You lost your equation. x(x - 2) = 0, which allows you to say x = 0 or x = 2.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Eigenvalue and matrix
  1. Eigenvalues of a matrix (Replies: 22)

Loading...