General notation of matrices

It is usually represented the matrices by capital letters and its elements by small letters, accompanied by two indexes which indicate, respectively, the row and the column that the element occupies. So an array THE of type m x n is represented by:

or abbreviated A = aijm x n, on what i and j represent, respectively, the row and column that the element occupies. For example, in the previous matrix, The23 is the element of the 2nd row and 3rd column.

In the matrix we have:

Or in matrix B = -1 0 2 5, we have:
The11 = -1
The12 = 0
The13 = 2
The14 = 5

Next: Row, Column, and Square Matrix