1. Not finding help here? Sign up for a free 30min 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!

Matrix multiplication

  1. Nov 7, 2009 #1
    1. The problem statement, all variables and given/known data
    Find A*B^T, where A=

    2 1
    5 3

    And B=

    1 -1 1
    -1 1 1


    2. Relevant equations

    n/a



    3. The attempt at a solution

    The problem is, is that if I get the transpose of B, I will end up with a 3x2 matrix. Isn't this impossible to multiply by a 2x2 matrix? Maybe the answers is just 'not possible', but I have a feeling I'm doing something wrong. Anybody got any pointers? Thanks!
     
  2. jcsd
  3. Nov 7, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    You are right, A*BT can't be computed. (AB)T can though, are you sure you weren't supposed to calculate that?
     
  4. Nov 7, 2009 #3
    The way it was actually written was BTA, so I think it made a point of showing that it wasn't (AB)T. So I'm thinking that the answer is that it can't be computed? Thanks for the quick reply!

    EDIT: ooooooooooh. Ooops. How embarassing. Of course it makes a difference when B comes first. Argh!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Matrix multiplication
  1. Matrix ? (Replies: 4)

  2. Vector multiplication (Replies: 6)

  3. Probability of multiples (Replies: 12)

Loading...