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Re: Almost symbolic computations (?)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90488] Re: [mg90466] Almost symbolic computations (?)
  • From: "W_Craig Carter" <ccarter at mit.edu>
  • Date: Thu, 10 Jul 2008 07:07:41 -0400 (EDT)
  • References: <200807101035.GAA15372@smc.vnet.net>

Hello Barbara,
I think this may be the answer to the first part of your question:

Needs["VectorAnalysis`"];
A = {a1[x, y, z], a2[x, y, z], a3[x, y, z]}
Curl[A, Cartesian[x, y, z]]

I am not sure what you are asking for the second.
Kind regards, WCC

On Thu, Jul 10, 2008 at 6:35 AM, Barbara Da Vinci
<barbaradavinci at tahoo.it> wrote:
> Dear MathGroup
>
> This is an example of the problem
> I'm facing.
>
> The code
>
>   Needs["VectorAnalysis`"];
>   Head /@ {ax, ay, az}
>   A = {ax, ay, az};
>     Curl[A]
>
> returns
>
> {Symbol, Symbol, Symbol}
> {0, 0, 0}
>
> Instead, I would get the
> well known symbolic form
>
> d_y az - d_z ay
> ...
>
> I have been trying, for
> a while, to perform string
> manipulations but that,
> of course, lays to ashes
> the possibility to recognize
>
> d_y az + d_y az = 2 d_y az
>
> and so on.
>
> Any way to get out of it ?
>
> Kind regards
>
>
> Barbara Da Vinci
>
>



-- 
W. Craig Carter


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