Question

Need help on a matrix operations question:

|21 -7| |-2 3|
|0 3 | |-1 6|
|11 -9| |2 -4|

It's a 2x3 matrix times another 2x3 matrix.

I know how to do 2x2 times 2x2 and 2x2 times 2x3, but unsure how to do 2x3 times 2x3.

Thanks!!!

Answer 1

are you sure there's such 2x3 . 2x3 matrix ? :) if i remember it right the second dimension of the matrix (let's say mxn ...second is n) have to match the first dimension of the second matrix...but maybe my memory isn't working nowaday :)..i'll follow this to see how other's opinions.

Answer 2

might have a problem with how I typed it... turns out that wasn't the original form

Answer 3

never mind, that was the right problem

Answer 4

2x3 time 3x something is ok ....not sure 2x3 time 2x3 :)

Answer 5

Any chance the answer is "no solution" ?

Answer 6

that is what i am thinking, it's been too long for me to remember all this :) but that's what i am incline to answer

Answer 7

found this online... credibility unknown, but it would suggest that perhaps you can't multiply matrices when the # rows & columns isn't compatible.

Answer 8

@tamtoan thanks for the assistance.... :) I assumed I'd get a stampede of matrix experts coming in to save the day, but like you, I don't remember all these details... :) Wish I did though... this is a no-kidding question from an offline "asker".

Answer 9

hopefully, we remember it right this time :)

Answer 10

not possible to do a matrix of 2x3 x 2x3

Answer 11

a 2x3 matrix times another 2x3 matrix does not have a defined answer

Answer 12

Thanks everyone! I began to suspect it wasn't defined, but I just wasn't sure. Appreciate the help...