This is LaTeX code:

[latex]
 
\left| \begin{array}{c c c c c}
a_1 + b_1 & b_1 & \dots & b_1 & b_1 \\
b_2 & a_2 + b_2 & \dots & b_2 & b_2 \\
\vdots & \vdots & \ddots & \vdots & \vdots \\
 b_{n - 1} & b_{n -1} & \dots & b_{n - 1} + a_{n - 1}& b_{n - 1} \\
 b_n & b_n & \dots & b_n & b_n + a_n\\
\end{array} \right| 
[/latex]