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Vectors

• To: mathgroup at smc.vnet.net
• Subject: [mg13894] Vectors
• From: Olivier Georg <ogeorg at imtsg12.epfl.ch>
• Date: Sun, 6 Sep 1998 02:55:31 -0400
• Organization: EPFL
• Sender: owner-wri-mathgroup at wolfram.com

Hi, 

I want to do symbolic calculation with vectors, in particular, I want to
do a vector product.  But if I declare:

   A = (a b c)

and do

   A x A

(which should give zero), but instead I get:

   Cross::"nonn1": "Not all of the arguments are vectors 
   of required length

since there's no way for mathematica to know that a, b and c represent
numerical value and not functions or lists. Is there a way around to
perform this kind of calculation ?

Please e-mail also, thanks,

Olivier
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