TABLE OF CONTENTS A matrix is simply a rectangular array of elements (numbers or symbols) arranged into rows and columns. It is written as follows:
The array of elements is usually enclosed in either brackets [] or braces {}. Symbolically a matrix is often designated by a boldface letter enclosed in brackets or braces.
A matrix has no numerical value. It is simply a convenient device for displaying arrays of numbers.
Each number appearing in a matrix is called an element. Since a matrix is, in general, a two-dimensional array of numbers, the elements of the matrix are identified by double subscripts. The first subscript designates the row in which an element is located and the second designates the column. Thus a 21 refers to the element in the second row, first column.
A matrix that contains only one column is referred to as a column matrix, and one that contains only one row is called a row matrix. Usually a column matrix is enclosed in braces. A square matrix contains the same number of rows and columns. The leading diagonal (also called the main or principal diagonal, or simply the diagonal) of a square matrix extends from the upper left corner to the lower right corner. Elements along the diagonal are referred to as diagonal elements. All other elements are off-diagonal elements. The diagonal extending from the upper right to the lower left has no special significance in...
