1. ## matrix

can someone tell me how you take the determinant of a 4X4 and 5X5 matrix

l a1 a2 a3 a4 a5 l
l b1 b2 b3 b4 b5 l
l c1 c2 c3 c4 c5 l
l d1 d2 d3 d4 d5 l
l e1 e2 e3 e4 e5 l

and

l a1 a2 a3 a4 l
l b1 b2 b3 b4 l
l c1 c2 c3 c4 l
l d1 d2 d3 d4 l

dan

3. I never used cofactors to find determinants of 3 by 3 matrices.

If I extended my method to 4 by 4 I would get for the matrix:

a b c d
e f g h
i. j. k l
m n o p

(afkp + bglm + chin + dejo) - (dgjm + cfip + belo + ahkn)

Is this correct? If so would I be able to extend it for any square matrix

4. Originally Posted by Glaysher
I never used cofactors to find determinants of 3 by 3 matrices.

If I extended my method to 4 by 4 I would get for the matrix:

a b c d
e f g h
i. j. k l
m n o p

(afkp + bglm + chin + dejo) - (dgjm + cfip + belo + ahkn)

Is this correct? If so would I be able to extend it for any square matrix
Sadly, I think that method only works for 3x3

5. Originally Posted by ThePerfectHacker
Sadly, I think that method only works for 3x3
i know that that's true...

6. Originally Posted by Glaysher
I never used cofactors to find determinants of 3 by 3 matrices.

If I extended my method to 4 by 4 I would get for the matrix:

a b c d
e f g h
i. j. k l
m n o p

(afkp + bglm + chin + dejo) - (dgjm + cfip + belo + ahkn)

Is this correct? If so would I be able to extend it for any square matrix
Is this not a particular case of Leibniz's formula (see here) ?

RonL

7. Originally Posted by CaptainBlack
Is this not a particular case of Leibniz's formula (see here) ?

RonL
But that is not necessary the ideal method. Because then you need to compute whether the premutations are even or odd--> That is time consuming.

8. Originally Posted by CaptainBlack
Is this not a particular case of Leibniz's formula (see here) ?

RonL
you tell me ... I did'nt get half of that explnation...
dan

9. Originally Posted by dan
you tell me ... I did'nt get half of that explnation...
dan
Yes it is

RonL

10. Originally Posted by ThePerfectHacker
But that is not necessary the ideal method. Because then you need to compute whether the premutations are even or odd--> That is time consuming.
Now if I recall I never said it was the ideal method of computing it.