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2 items are filed under this topic.
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The evaluation of a 3 by 3 determinant |
2016-02-19 |
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From Kristen:
What is the step-by-step process on how to evaluate the determinant of a 3*3 matrix, using the expansion method (not the diagonal method)
Answered by Penny Nom. |
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Determinants |
2008-05-02 |
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From Henry:
I have a question about solving 3x3 matrices.
The traditional way, or at least the way I've been taught, is that if one has a 3x3 matrix such as:
[ a b c ]
[ d e f ]
[ g h i ]
one solves it according to this formula:
[ei - hf) - (bi - hc) + (bf - ec) = determinant.
According to a book I'm now studying to prepare for the California CSET exam, there is another, easier, way to solve it:
[ a b c ] [ a b ]
[ d e f ] [ d e ]
[ g h i ] [ g h ]
In other words, one repeats the first two rows of the matrix and adds them to the right.
At this point, the determinant is calculated thus:
(aei) +(bfg) + (cdh) - (gec) - (hfa) - (idb).
Is this, in fact, correct?
Answered by Harley Weston. |
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