1.2.8 Determinant calculation

Problem: Calculate the determinant of \( (n+1) \)-th order \[ \Delta=\left|\begin{array}{ccccc} x & y_{1} & y_{2} & \ldots & y_{n} \\ y_{1} & x & y_{2} & \ldots & y_{n} \\ y_{1} & y_{2} & x & \ldots & y_{n} \\ \ldots & \ldots & \ldots & \ldots & \ldots \\ y_{1} & y_{2} & y_{3} & \ldots & x \end{array}\right| \text {. } \]