# Definition:Determinant/Matrix/Order 1

## Definition

Let $\mathbf A = \left[{a}\right]_1$ be a square matrix of order $1$.

That is, let:

$\mathbf A = \begin{bmatrix} a_{11} \end{bmatrix}$

Then the determinant of $\mathbf A$ is defined as:

$\begin{vmatrix} a_{11} \end{vmatrix} = \operatorname{sgn} \left({1}\right) a_{1 1} = a_{1 1}$

Thus the determinant of a single number is that number itself.