The horizontal arrays of a matrix are called its ROWS and the vertical arrays are called its COLUMNS. A matrix having rows and columns is said to have the order
A matrix of ORDER can be represented in the following form:
where is the entry at the intersection of the row and column.
In a more concise manner, we also denote the matrix by by suppressing its order.
Let Then and
A matrix having only one column is called a COLUMN VECTOR; and a matrix with only one row is called a ROW VECTOR.
WHENEVER A VECTOR IS USED, IT SHOULD BE UNDERSTOOD FROM THE CONTEXT WHETHER IT IS A ROW VECTOR OR A COLUMN VECTOR.
In other words, two matrices are said to be equal if they have the same order and their corresponding entries are equal.