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: Matrice word problem

  1. Jan 28, 2009 #1


    User Avatar

    1. The problem statement, all variables and given/known data
    Show that A + A(transpose) is symmetric for any square matrix A.

    2. Relevant equations
    A symmetric matrice is equal to A=A(transpose)

    3. The attempt at a solution

    I said A + A(transpose)
    = A(transpose) + A(transpose)
    = (A + A) (transpose)
    = A + A

    I don't know what else to do
  2. jcsd
  3. Jan 28, 2009 #2


    Staff: Mentor

    It looks like you're assuming that A is symmetric right at the start, which isn't information that you're given.

    Start with the definitions of AT and symmetric matrix.

    The definition you show for a symmetric matrix isn't right - I think you want this:
    A symmetric matrix A is such that A = AT. (A matrix can't be "equal" to an equation.)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook