Re: differentiation of cross products
- To: mathgroup at smc.vnet.net
- Subject: [mg16534] Re: differentiation of cross products
- From: "Peltio" <pelt.ioNOS at PAMiol.it>
- Date: Tue, 16 Mar 1999 04:00:12 -0500
- Organization: Peltio Inc.
- References: <7cd2ol$nmc@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Issac,
a rude way to do what you want is
Unprotect[Cross];
Cross /: D[Cross[f1_,f2_],x_]:=Cross[D[f1,x],f2]+Cross[f1,D[f2,x]]
Protect[Cross];
try it
D[Cross[g[t],h[t]],t]
Cross[g'[t], h[t]] + Cross[g[t], h'[t]]
Hope that helps,
Peltio,
peltioNOS at PAMusa.net
Issac Trotts wrote in message <7cd2ol$nmc at smc.vnet.net>...
>Can anyone tell me how to differentiate the cross product
>of two vector-valued functions in Mathematica?
>The input
>
>D[Cross[g[t],h[t]],t]
>
>results in the output
>
>h'[t] Cross^(0,1)[g[t], h[t]] + g'[t] Cross^(1,0)[g[t], h[t]]
>
>which is not correct. The correct answer would be
>
>Cross[g'[t], h[t]] + Cross[g[t], h'[t]]
>
>P.S.: Please send your response to trotts at ucdavis.edu .