|
One item is filed under this topic.
 |
|
|
|
|
|
|
|
|
Determinants |
2008-05-02 |
|
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. |
|
|
|
