If `A=[1 3 2 1]` , find the determinant of the matrix `A^2-2A` .

Explanation

To find the determinant of the matrix \( A^2 - 2A \) where \( A = \begin{pmatrix} 1 & 3 \\ 2 & 1 \end{pmatrix} \), we will follow these steps:

### Step 1: Calculate \( A^2 \)

To find \( A^2 \), we multiply matrix \( A \) by itself:

\[
A^2 = A \cdot A = \begin{pmatrix} 1 & 3 \\ 2 & 1 \end{pmatrix} \cdot \begin{pmatrix} 1 & 3 \\ 2 & 1 \end{pmatrix}
...