Determinant:

Square matrixes have a property known as a determinant. While a determinant of a matrix is written, it is symbolized through vertical bars rather than brackets around the numbers.  That differentiates the determinant from a matrix.  The determinant of a matrix is the reduction of the matrix to a single scalar number. A determinant of a matrix is found through "expanding" the matrix.   There are various methods of "expanding" a matrix and computing its determinant.  In this chapter, we will only look at a method known as "expansion by minors."

Before a large matrix determinant can be computed, we must learn how to calculate the determinant of a 2 x 2 matrix.  By the given definition, the determinant of a 2 x 2 matrix is calculated as follows: