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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>) |
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The determinant function for a 3 x 3 matrix is: | The determinant function for a 3 x 3 matrix is: | ||
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− | det(A) = [a<sub>11</sub> , a<sub>12</sub>, a<sub>13</sub> ; a<sub>21</sub> , a<sub>22</sub> , a<sub>23</sub> ; a<sub>31</sub> , a<sub>32</sub> , a<sub>33</sub>] | + | <math>det(A)=\left(\begin{array}{cccc}a11&a12&a13\\a21&a22&a23\\a31&a32&a33\end{array}\right)</math></math>det(A) = [a<sub>11</sub> , a<sub>12</sub>, a<sub>13</sub> ; a<sub>21</sub> , a<sub>22</sub> , a<sub>23</sub> ; a<sub>31</sub> , a<sub>32</sub> , a<sub>33</sub>] |
= '''(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>) ''' | = '''(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>) ''' |
Revision as of 14:55, 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) $</math>det(A) = [a11 , a12, a13 ; a21 , a22 , a23 ; a31 , a32 , a33]
= (a11 * a22 * a33) + (a12 * a23 * a31) + (a13 * a21 * a32) - (a12 * a21 * a33) - (a11 * a23 * a32) - (a13 * a22 * a31)