MaplePrimes - answers and comments on Question, Separating a curve into a dashed and a solid line at a specific point

intersection

acer — Wed, 02 Mar 2011 17:37:08 Z

Maybe the brute force way would do: find the x,y (err, Q1,Q2) values at the intersections. Then just draw eight curves instead of four. And have some of the eight get the dashed line style. See ?plot,option on chenging the line style.

Instead of creating all curves in a single plot structure right away, you could assign each to a name. Ie, P1:=plot3(....,Q1=-1..X, Q2=-1...1) where X is the Q1-coordinate of the intersection point. Analogously for the other curves, but some with the line style specified as an option. Then use plots:-display to show them all superimposed.

acer

Cheers!!!

rmjg20 — Wed, 02 Mar 2011 19:20:11 Z

Cheers!!!

spacecurve

Robert Israel — Wed, 02 Mar 2011 22:12:01 Z

plot3d is for surfaces, not curves. spacecurve in the plots package is for plotting curves in 3D. You could try something like this:

> P1 := 1 + 2*Q1^2; P11:= 2 + Q1^2;
   P2:= 3 + 4*Q2^2; P22:= 5 + 3*Q2^2;
   with(plots):
   solve(P1 = P11);
   m11, m12:= (min,max)(%);
   solve(P2 = P22);
   m21, m22:= (min,max)(%);
   display([spacecurve([Q1, 0, P1], Q1 = -3 .. m11, colour=red, linestyle=dash), 
                 spacecurve([Q1, 0, P1], Q1 = m11 .. m12, colour=red),   
                 spacecurve([Q1, 0, P1], Q1 = m12 .. 3, colour=red, linestyle=dash),
                 spacecurve([0, Q2, P2], Q2 = -3 .. m21, colour=blue),
                 spacecurve([0, Q2, P2], Q2 = m21 .. m22, colour=blue, linestyle=dash),
                 spacecurve([0, Q2, P2], Q2 = m22 .. 3, colour=blue)]);