kill(all)$

programming : maxima (graphics:draw),more than one parametric plot on the canvas, version 1.0
peter.vlasschaert@gmail.com,10/08/2019

load,'packages'

load(lrats);
load(draw);

How to draw phase (x,x'(=xx))

p1:x=A*exp(-t)+B*exp(-2*t);
p2:xx=diff(rhs(p1),t);

assume :A=1,B=0

p3:[A=1,B=0];

p3a:lratsubst(p3,[rhs(p1),rhs(p2)]);

wxplot2d([parametric,p3a[1],p3a[2],[t,-5,5]]);

load(draw);
wxdraw2d(
    color = red,
        parametric(p3a[1],p3a[2],t,-5,5)
);

how to build function: 
f1=f1(A,B,t)
f2=f2(A,B,t)

pareqs(a,b,f1,f2):=block([],
    pa: [A=a,B=b],
pb:lratsubst(pa,[f1,f2]));

p4a:pareqs(1,0,rhs(p1),rhs(p2));

wxdraw2d(
    color = red,
        parametric(p4a[1],p4a[2],t,-5,5)
);

p4b::pareqs(0,1,rhs(p1),rhs(p2));

combine : p4a & p4b
================

p5:append(p4a,p4b);

plot same graph : p4a,p4b
====================

wxdraw2d(
    /* first curve to draw to the canvas */
    color = red,
            parametric(p5[1],p5[2],t,-1,1),
    /*second curve to draw to the canvas*/
    color = blue,
            parametric(p5[3],p5[4],t,-1,1)
);