Further mathematics for Science and engineering / Nor Hanim Abd Rahman... [et al.]

Definition:
A set of real or complex numbers arranged in a rectangular array having m rows and n columns.
This set is called a matrix of order m x n (read as m by n).
The number aij is called an element in row i and column j.
The capital letters are used to denote matrices and the corresponding lower case letters are
used to denote the elements.