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Calculate Determinant
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det(\left(\begin{matrix}8&-1&9\\3&1&8\\11&0&17\end{matrix}\right))
Find the determinant of the matrix using the method of diagonals.
\left(\begin{matrix}8&-1&9&8&-1\\3&1&8&3&1\\11&0&17&11&0\end{matrix}\right)
Extend the original matrix by repeating the first two columns as the fourth and fifth columns.
8\times 17-8\times 11=48
Starting at the upper left entry, multiply down along the diagonals, and add the resulting products.
11\times 9+17\times 3\left(-1\right)=48
Starting at the lower left entry, multiply up along the diagonals, and add the resulting products.
48-48
Subtract the sum of the upward diagonal products from the sum of the downward diagonal products.
0
Subtract 48 from 48.
det(\left(\begin{matrix}8&-1&9\\3&1&8\\11&0&17\end{matrix}\right))
Find the determinant of the matrix using the method of expansion by minors (also known as expansion by cofactors).
8det(\left(\begin{matrix}1&8\\0&17\end{matrix}\right))-\left(-det(\left(\begin{matrix}3&8\\11&17\end{matrix}\right))\right)+9det(\left(\begin{matrix}3&1\\11&0\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.
8\times 17-\left(-\left(3\times 17-11\times 8\right)\right)+9\left(-11\right)
For the 2\times 2 matrix \left(\begin{matrix}a&b\\c&d\end{matrix}\right), the determinant is ad-bc.
8\times 17-\left(-\left(-37\right)\right)+9\left(-11\right)
Simplify.
0
Add the terms to obtain the final result.