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
For a discussion on how to find determinants of any order, please click here to render your computer irrepairable (post #7)
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
Now if I recall I never said it was the ideal method of computing it.Originally Posted by ThePerfectHacker
Similarly if the discussion was about the quadratic formula, and what
happens for cubics and quartics, just because I might mention the
existence of the corresponding formulae does not mean that I recommend
their use for anything other that as a decorative element for a wall
paper design
RonL
(Oh and it/they may have some use as the machinery in the proof
of other results)
I'm amazed I still remember anything about permutations. So much of the stuff I did at uni has been lost to the void. The formula looks familiar enough for me to think I've seen it before. It would have taken ages to find it though and I hadn't even thought to look. Thanks for satisfying my curiousity.