Question

Someone check my answer real quick?
The question asks if the product of these matrixes is defined or not, I answer not defined because the number of rows in the second matrix needs to be equal to the number of collumns in the first, right?
4 5
9 -2 1 7

Answer 1

@Hero @Luis_Rivera @RadEn

Answer 2

the first matrix is a 2x2 right?

Answer 3

and the second is a 1x2 matrix?

Answer 4

if both assumptions are correct, then yes, the product is not defined since the inner dimensions don't match

the equation # of columns in A = # of rows in B ... needs to be true for AB to be defined

Answer 5

in other words, you could do

1 x 2 x 2 x 2
(the 2's match up on the inside)

but not
2 x 2 x 1 x 2
(the 2 x 1 is a mis-match)

Answer 6

Sweet, thanks guys :)