Besides this being a ridiculus recursive formula for matrices. (it''s more sane if we stay within 2x2 or 3x3) Could you guys post anything that you might know regarding this "concept"? Where did it come from and what is it really used for? I can use it because I have no idea why I could "practically" use it. Thanx!! -Lewis [m80] Play QUADz MX @ www.m80produxions.com

The first that comes to mind is working out _if_ an inverse exists.

http://www.wikipedia.org/wiki/Determinant

More fun facts:

http://mathworld.wolfram.com/topics/Determinants.html

In Alg2 we used it to solve for variables in a matrix if thats any help.

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Brent Gunning | My Site

thanx fellaz... those are great resources... I''m going to check out the links now.

RapidStunna - did you use something called cramer''s rule? I gotta do some research on that guy. I think i loose sleep some nights because I go detail crazy.

Yes i''m a nut...

Anymore input? yummm

-Lewis [m80]
Play QUADz MX @
www.m80produxions.com

quote:

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RapidStunna - did you use something called cramer''s rule? I gotta do some research on that guy. I think i loose sleep some nights because I go detail crazy.

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Yes we did. I always prefered Augmented Matrices but determinants weren''t too bad either - they just got annoying to cross add everything. I like the more procedural approach. Anyway, yes we used Cramer''s Rule. Check out both.

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Brent Gunning | My Site

(let's hope the way i format this comes out right)

EDIT: no, it didn't. The first two matrices are:
|a|
|c|
and
|b|
|d|

and the last one is:
|a b|
|c d|

EDIT = END

I assume this has a 3d analog, but I just got up and can't be bothered to think about it. In any case, if you have two column vectors: |a| and |b|, the 2x2 matrix formed by the combination of
|c| |d|
these two (I defined it in my MA class as the :-) operation), you get a matrix of the form |a b|, now, the determinate of that
|c d|
matrix will give you the AREA of the parallelogram formed by those two vectors, when they're centered at (0,0), and their parallel sides. 1/2 of that will give you the area of the triangle formed by the two vectors and their resultant. There was some more stuff that follows that, I'll probably get back to you when I'm studying for the final.
Hope that helps/was undestandable.

P.S. there's also a 20 or so page, pretty detailed primer in matrices and vectors somewhere in the gamedev archives.

[edited by - IrateGoldfish on December 23, 2002 1:26:10 PM]

hey thanx man... i never understood that parallegram stuff... but while reading your definition of that function, I was looking at a figure in one of my math books. I feel like an idiot but thanx to you it makes sense. Why do people stay so technical with these texts? This is why I enjoy reading lamothe''s stuff. Funny & technical.

Thanx once again...

*cough*

Hehe

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