geometry app question... - 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 app question... (/thread-9296.html) |
geometry app question... - webmasterpdx - 10-15-2017 05:34 AM I'm trying to draw a circle, tangent to 3 lines using incircle(). I have 3 lines defined as: GA: line(y=(2*x+5)) GB: line(y=(-2*x-4)) GC: line(y=(-7*x+5)) and then I tried incircle as in: GD: incircle(GA,GB,GC) It draws the lines fine, but there is no circle on the plot screen.... What am I doing wrong? Thanks -Donald RE: geometry app question... - Arno K - 10-15-2017 06:06 AM On-calc help says incircle uses 3 Points rather than 3 lines. Arno RE: geometry app question... - webmasterpdx - 10-15-2017 06:43 AM You are right....but that's kinda screwed up, as it's supposed to draw a circle that is a tangent to 3 sides of a triangle. When I specify 3 points, I don't see the edges of the triangle....just the vertices and a circle in the middle somewhere....i.e. You can't see the tangents. RE: geometry app question... - Didier Lachieze - 10-15-2017 07:06 AM Starting from your 3 lines you can then define the triangle vertices and draw the circle : GA:= line(y = (2*x+5)); GB:= line(y = (-2*x-4)); GC:= line(y = (-7*x+5)); GD:= single_inter(GA,GB); GE:= single_inter(GB,GC); GG:= single_inter(GA,GC); GH:= incircle(GD,GE,GG); If you have just 3 points GA,GB,GC you can draw the triangle with triangle(GA,GB,GC) RE: geometry app question... - webmasterpdx - 10-15-2017 07:22 AM Cool! Thank you! -D RE: geometry app question... - Brad Barton - 10-16-2017 02:07 PM (10-15-2017 07:06 AM)Didier Lachieze Wrote: Starting from your 3 lines you can then define the triangle vertices and draw the circle : I tried this out today, and it looks pretty good in the plot screen. However when I try to generate the coordinates of the intersection of the circle and any one of the tangent lines, I get an imaginary result. Does this mean that the circle and the lines don't truly intersect? RE: geometry app question... - Arno K - 10-16-2017 08:25 PM If I remember correctly, points in geometry are represented by complex numbers. Arno RE: geometry app question... - Brad Barton - 10-16-2017 08:28 PM (10-16-2017 08:25 PM)Arno K Wrote: If I remember correctly, points in geometry are represented by complex numbers. Thanks, that explains it. |