Re: Curl
- To: mathgroup at smc.vnet.net
- Subject: [mg34889] Re: [mg34875] Curl
- From: BobHanlon at aol.com
- Date: Wed, 12 Jun 2002 02:15:16 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
In a message dated 6/11/02 6:09:38 AM, jdeacon at jdl.co.uk writes:
>I must be getting the coordinate system wrong. I want to
>calculate something like curl F where
> F(x,y,z) = ixz + jyz + ky^2
>where i, j and k are the unit vectors in the x, y and z
>directions respectively.
>
> << Calculus`VectorAnalysis`
> SetCoordinates[Cartesian[x, y, z ]]
> Curl[{xz, yz, -y^2}]
>produces
> {-2 y, 0, 0}
>Yet I would swear it should be -3yi + xj
>
>What am I doing wrong?
>
Needs["Calculus`VectorAnalysis`"];
SetCoordinates[Cartesian[x,y,z]];
Curl[{x*z,y*z,-y^2}]
{-3*y, x, 0}
Use an explicit multiplication operator and you won't have to remember to put
a space between the variables.
Bob Hanlon
Chantilly, VA USA