I''ve come across an old maths text which uses notation i don''t recognise example: area of a triangle given by

1   | x1 y1  1 |
- * | x2 y2  1 |
2   | x3 y3  1 |
 

(where the lines drawn as | are solid) what should I make of this? ******** A Problem Worthy of Attack Proves It''s Worth by Fighting Back

Matrix multiplication. Can''t help you more though; it''s part of Mathematics A here, and I only have Mathematics B. But I think there are articles about this around here, since it''s a really basic part of most 3D graphics programming.

It represents the determinant of the matrix.

Yeah, its the determinant.
|a b|
|c d| = ad-bc

I know that one ^ is right.

|a b c||d e f| = a*|e f| - b*|d f| + c*|d e||g h i|     |h i|     |g i|     |g h| 

or something along those lines.
(I hope that got aligned correctly...)

edit: dammit! why does it compress the spaces? hopefully, you understand what I mean.



[edited by - vanillacoke on May 13, 2003 4:21:28 PM]

[grhodes_at_work edit: added "code" tags to achieve monospace font + corrected an error in the 3x3 determinant]

[edited by - grhodes_at_work on May 16, 2003 3:36:15 PM]