Re: CrossProduct in Spherical Coordinates

*To*: mathgroup at smc.vnet.net*Subject*: [mg75317] Re: CrossProduct in Spherical Coordinates*From*: Roger Bagula <rlbagula at sbcglobal.net>*Date*: Wed, 25 Apr 2007 05:32:26 -0400 (EDT)*References*: <f0kbsf$r1k$1@smc.vnet.net>

gogoant06 at yahoo.com.hk wrote: >Dear all, > >I am really new to mathematica and I have met a damn simple problem. > >In[1]:= ><<Calculus`VectorAnalysis` > >In[2]:= >CrossProduct[{1,0,0},{0,1,0},Spherical] > >Out[2]= >{0,0,0} > >Why? Isn't the result supposed to be {0,0,1}, even in spherical >coordinates? > >best regards, >lion > > > > The answer that you are thinking about it wrong: spherical polar coordinates are { r, theta, phi} without an r value in the coordinate the output will always be zero. You need at least an angle and a radius to get any output at all. Examples: In[32]:= CrossProduct[{1,0,1},{1,1,0},Spherical] Out[32]= {Sin[1], =CF=80/2, =CF=80/2} In[33]:= CrossProduct[{1,0,1},{0,1,1},Spherical] Out[33]= {0,0,0}