Finding the determinant of a 3x3 matrix is much more complicated than finding it in a 2x2 matrix. You start out by treating the lower right of the matrix as a 2x2 matrix and we expand out from there. It is possible to have a negative value for the determinant. The area on the other hand cannot be negative. To see a complete walk through of one of this problem either scroll to the bottom or open up one of the lessons.
These worksheets explain how to calculate the determinant of a 3 x 3 matrix using simple cross multiplication and subtraction and the diagonals method.
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Determinants in a 3 x 3 Matrix Worksheets
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This lesson explains how to find the determinant of a 3x3 matrix by sizing everything up for yourself. A sample problem is solved, and two practice problems are provided.
See how your students are making out with this skill. Three problems are provided, and space is included for students to copy the correct answer when given.
We get one more go at the 3 x 3 matrix using the diagonals approach. Three problems are provided, and space is included for students to copy the correct answer when given.
How Do You Find the Determinants in a 3 x 3 Matrix?
However, if you want to find out the determinant of 3x3 matrix, then the number of steps somewhat change. Let us look at the following example.
If we look back to what we did, we can see that we expanded by 1st column and placed an imaginary pointer on its every element. In the middle of it, we neglected all elements in front, above, and below it. We also added a minus sign before the second element. Now, we will resolve the 2x2 matrices with the same method as mentioned above.
