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: Orthogonal Matrix

  1. Apr 7, 2010 #1
    Prove that the transpose of an orthogonal matrix is an orthogonal matrix.

    I think that the Kronecker delta needs to be used but not sure how to write it out.
     
  2. jcsd
  3. Apr 7, 2010 #2

    Fredrik

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Do you know the definition of an orthogonal matrix?
     
  4. Apr 7, 2010 #3
    The columns most for an orthogonal set.
     
  5. Apr 7, 2010 #4

    Mark44

    Staff: Mentor

    Wouldn't that be information you should include in your first post, as either given/known data or relevant equations?

    That's why those sections are in the problem template. We shouldn't have to pry that information out of you.
     
  6. Apr 7, 2010 #5
    I find that trivial because if I didn't know that, why would I be trying to prove anything related to orthogonal matrices?
     
  7. Apr 7, 2010 #6

    Mark44

    Staff: Mentor

    How do we know that you know that? Our only evidence of what you know or don't know is the information you include.
     
  8. Apr 7, 2010 #7
    Because I have no business trying to prove something I know nothing about.
     
  9. Apr 7, 2010 #8

    Mark44

    Staff: Mentor

    So convince us that you know something about it by including the basic information when you post.
     
  10. Apr 14, 2010 #9

    Fredrik

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There's another definition of "orthogonal matrix" that's more common (I think), and definitely more useful in this case. (It makes the problem trivial). Do you know any other statements about orthogonal matrices? Something that holds if, and only if, the columns are mutually orthogonal?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook