[R] How to get the normal direction to a plane?

[Gabor Grothendieck]

I just reread my post and "a unique answer" should be "an answer that can
be chosen in a unique way based on certain additional standard conventions"


Gabor Grothendieck <ggrothendieck <at> myway.com> writes:

: 
: In R^3 there is a unique answer if the points don't all lie on a line.
: See the discussion a few weeks ago on the list available at this thread:
: 
:    http://tolstoy.newcastle.edu.au/R/help/04/05/1487.html
: 
: Also you might want to google for    
: 
:    cross product
: 
: 
: Fred <fzh113 <at> hecky.it.northwestern.edu> writes:
: 
: : 
: : Dear All
: :  
: : Maybe the following is a stupid question.
: : Assume I have 3 coordinate points (not limited to be in 2D or 3D space)
: : a, b, c.
: : It is known that these 3 points will define a plane.
: : The problem is how to get the normal direction that is orthogonal to
: : this plane.
: : 
: : Is there an easy way to calculate it using the values of a, b, and c?
: : 
: : Thanks for any point or help on this.
: : 
: : Fred
: 
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