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}