10 Mar 2021

Posted on:

05 Mar 2021

0

# Dot product of matrices video

Its a bit unclear why matrices are being multiplied here when other tensors must be equal dimension. Here in this video (Dot product of Matrices), they're now suggesting to multiply a level 2 matrix with a level 3 without explaining why this is the case and why it is an exception to the rule. I'd like to know the logic behind this so that I can learn it as opposed to merely just memorizing it

Instructor
Posted on:

10 Mar 2021

0

Hi Trevor,
I suppose your question concerns the multiplication of the 2x3 matrix with the 3x2 matrix as shown in the lesson.
So the first important thing is to check whether these matrices are compatible, and they are because their forms are matching-namely the number of columns in the first matrix which is 3 is the same as the number of rows in the second one(again 3).
After that we perform the multiplication itself by taking the dot product of each row vector of the first matrix with each
column vector of the second one.
I hope this helps!

Best,
365 Eli