Re: Curl and Div problems

*To*: mathgroup at smc.vnet.net*Subject*: [mg115507] Re: Curl and Div problems*From*: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>*Date*: Thu, 13 Jan 2011 03:25:37 -0500 (EST)

Hi, how should Mathematica know, that your cartesian coordinates are named x,y and z? This is one of the first things you can read in the tutorial VectorAnalysis/tutorial/VectorAnalysis so what about In[1]:= Needs["VectorAnalysis`"] Div[{x^2 y, x z, x^2 y^3}, Cartesian[x, y, z]] Out[2]= 2 x y Hope this helps, Cheers Patrick On Wed, 2011-01-12 at 04:07 -0500, sean k wrote: > I'm having problems with VectorAnalysis package. > > Within the documentation center, the package loads and works fine. > > But in a notebook, it seems to highlight Curl in red and neither Div > or Curl works properly. > > Needs["VectorAnalysis`"] > > {D[x^2 y, x] + D[ x z, y] + D[ x^2 y^3, z]} > > Div[{x^2 y, x z, x^2 y^3}] > > gives different answers. > > {2 x y} > 0 > > > Curl[{x^2 y, x z, x^2 y^3}] > > gives > > {0,0,0} > > > I'm on windows vista home edition, 64 bit, Mathematica 8.0. > > Does anyone else have this problem? > >