Geometry - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: Geometry (/thread-5431.html) Geometry - lrdheat - 01-01-2016 09:07 PM After making an ellipse in geometry app, how do I use measure to get it's area? I keep getting zero! I'm not getting this...! Thanks! (The geometry app looks like fun). RE: Geometry - Fortin - 01-01-2016 09:31 PM (01-01-2016 09:07 PM)lrdheat Wrote:  After making an ellipse in geometry app, how do I use measure to get it's area? I keep getting zero! I'm not getting this...! Thanks! (The geometry app looks like fun). It returns 0 for me as well. The help for area() does not mention anything specifically about working for an ellipse. It does mention and returns non-zero results for circles however. I'm guessing that it's a limitation. RE: Geometry - parisse - 01-02-2016 08:46 AM If you don't find information in HP documentation, you should have a look at Xcas: area currently supports circles and polygons. There is no special object for conics, they are stored as parametric curves in the CAS (Geometry uses CAS objects). I can extend the area command to parametric curves (including ellipses but also function and polar plots) using Green-Riemann theorem, but for non closed curves you will be surprised by the sign. Indeed I must close the curve to apply Green-Riemann, it's natural to close it with vertical segments at the boundaries and the Ox axis, but then you will not follow the curve in the trigonometric way : I will in fact compute int(-y*dx) along the curve. Note also that the area will be computed in approx mode (because the plotting functions do numeric evaluation of the boundaries). RE: Geometry - math7 - 01-17-2018 03:43 AM Parisse.... Have you ever added this functionality or have you not been present in the new update? RE: Geometry - parisse - 01-17-2018 07:25 PM It's not implemented.