I don't have programs like MAthematica or Maple that plot vector fields out of the box, the ones I use are Maxima and Scilab for simbolic/numeric, and none of them can easly plot 3d vector fields, so if someone can plot this one for me, I will appreciate it: $$ \left( \frac{\cot (\theta)}{r^3},\frac{1}{r^3},0 \right)$$
It's in spherical coordinates
Thanks in advance. PS: I tried with wolfram alpha but it didn't recognise it. and btw, if someone knows a good free program to do this stuff, please let me know (I used to have a license for Maple from college but I don't have it anymore)
EDIT: The spherical coordinates are in this case: $(r,\theta,\phi)$, where $\theta$ is the angle with ther vertical from 0 when it's vertical, in the direction of z axis, and $\pi$ when it's in the direction of -z axis. $\phi\in (0,2\pi)$
Have you tried this online MMA Web Based tool to do a 3D Plot of Vector Fields?
You might also try have a look here and see if any of the free SW listed works for you (GNU Plot, JavaView, Visual Data...).
Have fun!
Regards