Question

The sizes of two matrices A and B are given. Find the sizes of the product AB and the product BA, whenever these products exist.

Answer 1

A.

Given that the number of columns of the first matrix A is equal to the number of rows of the second matrix B, we can multiply them and the result is a matrix of size 1x1.

B.

Given that the number of columns of the first matrix B is equal to the number of rows of the second matrix A, we can multiply them and the result is a matrix of size 4x4.