1.2.13 Determinant calculation

Problem: Calculate the determinant \( \Delta_{n} \) of order \( n \times n \). \[ \Delta_{n}=\left|\begin{array}{ccccc} 1 & 1 & \cdots & 1 & -n \\ 1 & 1 & \cdots & -n & 1 \\ \cdots & \cdots & \cdots & \cdots & \cdots \\ 1 & -n & \cdots & 1 & 1 \\ -n & 1 & \cdots & 1 & 1 \end{array}\right| \]