https://johncarlosbaez.wordpress.com/2015/03/17/planets_in_the_4th_dimension/ looks like a plausible approach for finding parametric descriptions of ellipses.
I've not tried it, though. Thanks, -- Raul On Sat, Mar 7, 2015 at 2:35 PM, Skip Cave <[email protected]> wrote: > Raul, Thanks for the links! That's what I needed. I didn't think about > looking in the Studio Labs for the Plot documentation. The final secret is > to throw away the imaginary parts of the ellipse equation so all z outside > the ellipse is zero: > > a =.1 > > b=. 1.7 > > c =. 1.5 > > x =. 5 %~21 21 $ i:10 > > y =. |: x > > z =. {. |: +. c * ((1 - ((x^2)%(a^2)) + ((y^2)%(b^2))))^0.5 > > 'surface' plot z > > > Here's the plot: http://bit.ly/1GbYuy1 > > > The axes should be 1, 1,7 and 1.5, but they are not, so I need to look at > that. > > > Skip > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
