If matrix A is size (m × n) and matrix B is size (n × k), then the product of matrix A times matrix B is
another matrix, AB, of size (m × k). To find the element of the ith row and jth column of the product
matrix, multiply each element of the ith row of A by the corresponding element in the jth column of B
and then add these products.
Example: Find the product of matrices A and B. (Matrix A and B are identical because we want to
multiply matrix A by itself.)