Skip to main content
Calculate Determinant
Tick mark Image
Evaluate
Tick mark Image

Share

det(\left(\begin{matrix}5&6&7\\8&9&10\\11&12&13\end{matrix}\right))
Find the determinant of the matrix using the method of diagonals.
\left(\begin{matrix}5&6&7&5&6\\8&9&10&8&9\\11&12&13&11&12\end{matrix}\right)
Extend the original matrix by repeating the first two columns as the fourth and fifth columns.
5\times 9\times 13+6\times 10\times 11+7\times 8\times 12=1917
Starting at the upper left entry, multiply down along the diagonals, and add the resulting products.
11\times 9\times 7+12\times 10\times 5+13\times 8\times 6=1917
Starting at the lower left entry, multiply up along the diagonals, and add the resulting products.
1917-1917
Subtract the sum of the upward diagonal products from the sum of the downward diagonal products.
0
Subtract 1917 from 1917.
det(\left(\begin{matrix}5&6&7\\8&9&10\\11&12&13\end{matrix}\right))
Find the determinant of the matrix using the method of expansion by minors (also known as expansion by cofactors).
5det(\left(\begin{matrix}9&10\\12&13\end{matrix}\right))-6det(\left(\begin{matrix}8&10\\11&13\end{matrix}\right))+7det(\left(\begin{matrix}8&9\\11&12\end{matrix}\right))
To expand by minors, multiply each element of the first row by its minor, which is the determinant of the 2\times 2 matrix created by deleting the row and column containing that element, then multiply by the element's position sign.
5\left(9\times 13-12\times 10\right)-6\left(8\times 13-11\times 10\right)+7\left(8\times 12-11\times 9\right)
For the 2\times 2 matrix \left(\begin{matrix}a&b\\c&d\end{matrix}\right), the determinant is ad-bc.
5\left(-3\right)-6\left(-6\right)+7\left(-3\right)
Simplify.
0
Add the terms to obtain the final result.