Upper Triangular Matrix/Examples/Not in Echelon Form

Example of Upper Triangular Matrix

This is an arbitrary example of an upper triangular square matrix which is specifically not in echelon form (non-unity variant):

$\begin {pmatrix} 1 & 2 & 3 & 4 \\ 0 & 0 & 6 & 7 \\ 0 & 0 & 8 & 9 \\ 0 & 0 & 0 & 10 \end {pmatrix}$

Sources

• 1998: Richard Kaye and Robert Wilson: Linear Algebra ... (previous) ... (next): Part $\text I$: Matrices and vector spaces: $1$ Matrices: Exercises: $1.8$