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Re: Vectors

  • To: mathgroup at smc.vnet.net
  • Subject: [mg13917] Re: [mg13894] Vectors
  • From: "Jens-Peer Kuska" <kuska at linmpi.mpg.de>
  • Date: Mon, 7 Sep 1998 01:22:42 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

vec={a,b,c}

and

Cross[vec,vec]

works correct, and gives 0! 
Or did You type "(a b c)" ? 
If Your answer is "Yes" You shoud 
take three weeks to read "The Book"
about Mathematica.

Hope that helps
  Jens

-----Original Message-----
From: Olivier Georg <ogeorg at imtsg12.epfl.ch> To: mathgroup at smc.vnet.net
Subject: [mg13917] [mg13894] Vectors


>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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