Matrix multiplication

  • #1

Homework Statement


Find A*B^T, where A=

2 1
5 3

And B=

1 -1 1
-1 1 1


Homework Equations



n/a



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!
 

Answers and Replies

  • #2
rock.freak667
Homework Helper
6,230
31
You are right, A*BT can't be computed. (AB)T can though, are you sure you weren't supposed to calculate that?
 
  • #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!
 

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