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− | <math>det(A)=\left(\begin{array}{cccc}a11&a12\\a21&a22\end{array}\right)</math> = ('''a<sub>11</sub> * a<sub>22)</sub> - (a<sub>12</sub> * a'''<sub>'''21'''</sub><sub>''' '''</sub>) | + | <math>det(A)=\left(\begin{array}{cccc}a11&a12\\a21&a22\end{array}\right)</math> |
+ | |||
+ | = ('''a<sub>11</sub> * a<sub>22)</sub> - (a<sub>12</sub> * a'''<sub>'''21'''</sub><sub>''' '''</sub>) | ||
| | ||
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− | <math>det(A)=\left(\begin{array}{cccc}a11&a12&a13\\a21&a22&a23\\a31&a32&a33\end{array}\right)</math></ | + | <math>det(A)=\left(\begin{array}{cccc}a11&a12&a13\\a21&a22&a23\\a31&a32&a33\end{array}\right)</math> |
+ | |||
+ | = '''(a<sub>11</sub> * a<sub>22</sub> * a<sub>33</sub>) + (a<sub>12</sub> * a<sub>23</sub> * a<sub>31</sub>) + (a<sub>13</sub> * a<sub>21</sub> * a<sub>32</sub>) - (a<sub>12</sub> * a<sub>21</sub> * a<sub>33</sub>) - (a<sub>11</sub> * a<sub>23</sub> * a<sub>32</sub>) - (a<sub>13</sub> * a<sub>22</sub> * a<sub>31</sub>) ''' | ||
+ | |||
+ | ---- | ||
+ | ==Properties of Determinants== | ||
+ | |||
− | |||
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<br> | <br> |
Revision as of 14:58, 7 December 2011
Determinants
If A is a square matrix then the determinant function is denoted by det and det(A)
For an instance we have a 2 x 2 matrix denominated A, therefore:
det(A) = [a11 , a12 ; a21 , a22 ]
As we already defined the determinant function we can write some formulas. The formulas for any 2 x 2 and 3 x 3 matrix will be:
The determinant function for a 2 x 2 matrix is:
$ det(A)=\left(\begin{array}{cccc}a11&a12\\a21&a22\end{array}\right) $
= (a11 * a22) - (a12 * a21 )
The determinant function for a 3 x 3 matrix is:
$ det(A)=\left(\begin{array}{cccc}a11&a12&a13\\a21&a22&a23\\a31&a32&a33\end{array}\right) $
= (a11 * a22 * a33) + (a12 * a23 * a31) + (a13 * a21 * a32) - (a12 * a21 * a33) - (a11 * a23 * a32) - (a13 * a22 * a31)
Properties of Determinants