Wikipedia:Reference desk/Archives/Mathematics/2007 January 13

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January 13

Does this equation mean anything?

Recently while trying to test different fortran compilers, I invented this formula:

d = (a*b - a*c)*(a*b - b*c)*(b*c - a*c)

It served to reveal different behaviour between 2 cpus which were meant to be the same. I could imagine using it as a basis for art, but does it mean anything? —The preceding unsigned comment was added by 81.57.5.115 (talk) 10:46, 13 January 2007 (UTC).

No.--80.136.167.106 11:04, 13 January 2007 (UTC)

You might be interested in symmetric polynomials. --HappyCamper 13:28, 13 January 2007 (UTC)

It does graph rather interestingly. --jpgordon^∇∆∇∆ 00:36, 14 January 2007 (UTC)

How do you graph it ? Implicit equation in 3D ? --Xedi 14:45, 14 January 2007 (UTC)

You can simplify it easily: d = a*b*c*(b-c)*(a-c)*(b-a), the zero set of which is six planes a=0,b=0,c=0,b=c,a=c,b=a. It has rotational symmetry about the line a=b=c. --Salix alba (talk) 23:25, 14 January 2007 (UTC)

That is the cross product. It is used to find a vector perpendicular to two other vectors. Rya Min 19:57, 15 January 2007 (UTC)

No, it's not. It's a function from three scalar values to one scalar value, not from two vector values to a vector value. Rawling4851 15:06, 16 January 2007 (UTC)

It could be the dot product? Rya Min 21:52, 16 January 2007 (UTC)

Again: no.--80.136.162.146 21:57, 16 January 2007 (UTC)

oh. Then I dont know. I actually realized that it wasnt the dot product write after i clicked "save page." Im just gonna quit trying now. Rya Min 02:23, 17 January 2007 (UTC)