Upper Triangular Matrix/Examples/Square Matrix

Example of Upper Triangular Matrix
An upper triangular square matrix of order $n$:


 * $\mathbf U = \begin{bmatrix}

a_{11} & a_{12} & a_{13} & \cdots &    a_{1, n - 1} &      a_{1n} \\ 0 & a_{22} & a_{23} & \cdots &    a_{2, n - 1} &      a_{2n} \\ 0 &     0 & a_{33} & \cdots &     a_{3, n - 1} &      a_{3n} \\ \vdots & \vdots & \vdots & \ddots &          \vdots &      \vdots  \\ 0 &     0 &      0 & \cdots & a_{n - 1, n - 1} & a_{n - 1, n} \\ 0 &     0 &      0 & \cdots &                0 &       a_{nn} \\ \end{bmatrix}$