A matrix with the same number of columns as rows is called a square matrix. The determinant is a real number which is associated with each square matrix having real number entries.

ex.

which is defined as;

The determinant of a square 2×2 matrix is defined as;

This is commonly called the determinant. A 2×2 determinant is also called a second order determinant.

ex.
Compute the determinant:

Determinants are used also to solve system of equations with the help of Cramer's Rule [1].