An Upper Triangular [[Matrix]] is a square matrix that has all zeros below its diagonal. this is what obsidian was made for The [[Determinant]] of a [[Upper Triangular Matrix]] is the product of its diagonals. >[!example] >$\left|\begin{matrix} >1&2&-1\\0&-2&0\\0&0&-4 >\end{matrix}{ >}\right| >= 1 \cdot \pa{-2} \cdot 4 >$