Understanding Non-Square Matrix Multiplication

Through this tutorial, I want to explain how to compuate the multiplications of non-square matrix; for example, the result of multiplying a $2 \times 5$ matrix by a $5 \times 2$ matrix (a by c in the following example.)

import numpy as np

a = np.array([[1, 2,7,9,10], [3, 4,5,12,11]])
a

array([[ 1, 2, 7, 9, 10], [ 3, 4, 5, 12, 11]])

a …