Re: Re: Derivative of a funtion evaluated at a point in 3D

*To*: mathgroup at smc.vnet.net*Subject*: [mg44474] Re: [mg44468] Re: Derivative of a funtion evaluated at a point in 3D*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 12 Nov 2003 08:01:25 -0500 (EST)*References*: <boign7$oj1$1@smc.vnet.net> <200311110055.TAA25212@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I guess nobody answered you because everyone expected someone else to do so. The answer is pretty trivial, in Mathematica you don't define a function by: >> F[p1,p2,p3,p4] = stuff but by F[p1_,p2_,p3_,p4_] = stuff You then use D[F[p1,p2,p3,p4],p1] to get the first derivative with respect to p1, D[F[p1,p2,p3,p4],{p1,2}] to get the second and so on. I am afraid there are no shortcuts in Mathematica and you just have to learn the basics yourself. Andrzej Kozlowski On 11 Nov 2003, at 09:55, mroc wrote: > mroc_1000 at hotmail.com (mroc) wrote in message > news:<boign7$oj1$1 at smc.vnet.net>... >> Hello, I am totally new to Mathematica and trying to program a simple >> FEM-type problem. I am trying to take the partial derivative >> (symbolically) of an expression that is a function of four points in >> 3D. All I can think of to do is F[p1,p2,p3,p4] = stuff then >> D[F,p1,p2,p3,p4] . But I keep getting a zero expression as a result. >> (where stuff is a nasty combination of these points) Any thoughts? > > Anyone? What am I missing? Is this question too easy or too hard? > > >

**References**:**Re: Derivative of a funtion evaluated at a point in 3D***From:*mroc_1000@hotmail.com (mroc)