Re: Coordinate conversion with Grad

*To*: mathgroup at smc.vnet.net*Subject*: [mg75914] Re: Coordinate conversion with Grad*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sun, 13 May 2007 05:47:54 -0400 (EDT)*References*: <f23pvb$nqd$1@smc.vnet.net>

Hi, a) CoordinatesToCartesian[] will do that b) you are sure that a {0,-Sin[Ttheta]/Rr,0} in cylindircal coordinates with r=0 is not the origin ?? Regards Jens laxmipt at gmail.com wrote: > I am using Mathematica 5.2. > I wish to do coordinate transformations for differential geometry. > For > example transform a Grad from a cylindrical system to a Cartesian > system: > For example: > In[1]:= << Calculus`VectorAnalysis`; > SetCoordinates[Cylindrical] > > Out[2]:=Cylindrical[Rr, Ttheta, Zz] > > In[3]:= Grad[Cos[Ttheta], Cylindrical[Rr, Ttheta, Zz]] > > Out[4]:={0,-Sin[Ttheta]/Rr,0} > > The above Grad vector refers to the cylindrical system. How can I get > Mathematica to convert it into the corresponding gradient in the > Cartesian > system, which would become: > {sin^2(Ttheta)/Sqrt[x^2+y^2], sin(Ttheta)Cos(Ttheta)/Sqrt[x^2+y^2],0} > > Thanks! > Sachin > >