Le Forgeron <jgr### [at] freefr> wrote:
> Le 04.11.2007 17:16, alphaQuad nous fit lire :
>
> > apparently I am in similiar company as no else can either.
> >
>
> Stop whining... it won't help to get any result.
>
> > the task:
> > Area = abs(   (xB*yA - xA*yB)  + (xC*yB -x B*yC)+( xA*yC - xC*yA ) ) /2
>
> This formula looks bogus.
>
> We already know that
>
> Area = || AB x AC ||
>            -------------
>                    2
>
> Let's make a numerical application with A(0,-1) B(1,0) and C(0,1)
>
>  abs ( (-1 - 0) + (0 - 1) + ( 0 +1 ) ) /2 ---> abs ( -1 ) /2 --> 1/2
> (wrong)
I get ( (-1 - 0) + (0 - 1) + ( 0 + 0 ) ) /2= -1, which is correct.

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