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curve-fittingcomplex-numbersexponentialmaximaspiral

How to find curve which runs through complex points?


I have lists of complex points: orbit of complex point z under quadratic function

 f(z) = z*z

I know that lists are:

  • z, z^2, z^4, z^8, ...
  • (r,t), (r^2, 2*t), ..., (r^(2^n), t*2^n)

where :

  • r = abs(z)
  • t = arg(z)

So I think that these curve will be exponential spirals.

But my code:

 GiveParametric(radius,tMin,tMax) := 
 parametric(radius^t*cos(t),radius^t*sin(t),t,tMin,tMax)$

 GivePolar(radius, tMin,tMax) :=  polar(radius^(2^t),t,tMin,tMax)$

does not work.

Here is the image of 3 orbits (lists). Each list sould have it's own curve ( function) enter image description here

Question :

How to draw (or find equations of) curves which runs through these points ?


Solution

  • enter image description here I have used definition to draw sequence of points joined by lines

    GiveContOrbit(r0,a0,tMin, tMax, dt ):=
     block(
       [Orbit,a,r,t, b],
       t : tMin,
       b: 2^t,
       a:a0*b,
       r: r0^b,
       z: GiveZ(r,a),
       Orbit:[[realpart(z),imagpart(z)]], 
       for t:tMin thru tMax step dt do
        ( 
            b: 2^t,
        a:a0*b,
        r: r0^b,
        z: GiveZ(r,a), 
        Orbit:endcons([realpart(z),imagpart(z)],Orbit)),
        return(Orbit) 
        )$
    

    This in not what I wanted but seems to be a good aproximation. As I see curves intersects.