Solving Matrix Multiplication: A*B^T with A=2,1;5,3 and B=1,-1,1;-1,1,1

[lagwagon555]

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!

 

[rock.freak667]

You are right, A*B^T can't be computed. (AB)^T can though, are you sure you weren't supposed to calculate that?

 

[lagwagon555]

The way it was actually written was B^TA, 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!