Re: Wrong behavior of CrossProduct

*To*: mathgroup at smc.vnet.net*Subject*: [mg8003] Re: Wrong behavior of CrossProduct*From*: Sergio Rojas <sergio at scisun.sci.ccny.cuny.edu>*Date*: Wed, 30 Jul 1997 23:57:57 -0400*Sender*: owner-wri-mathgroup at wolfram.com

On Mon, 28 Jul 1997, Paul Abbott wrote: > Sergio Rojas wrote: > > > In[1]:= Needs["Calculus`VectorAnalysis`"]; > > In[2]:= SetCoordinates[Spherical[r,theta,phi]]; > > In[3]:= V = {a1,a2,0}; > > In[4]:= U = {0, 0, 1}; > > In[5]:= CrossProduct[U,V] > > Out[5]= {0, 0, 0} > > (* Again, wrong result. Same results were obtained on *) > > Why do you say this result is wrong? Your vector U={0, 0, > 1}=={r,theta,phi} has zero length. > However, according to Arfken's Mathematical Methods for Physicists, Third Edition, Pg. 88, equation 2.11b, the answer should be (a2,-a1,0). It has the same form as in Cartesian coordinates but with different meaning for the symbols a1 and a2. Rojas E-mail: sergio at scisun.sci.ccny.cuny.edu