clear all;
close all;

xr1 = solve('abs(1+x)=1.0')
xr2 = solve('abs(1+x+x^2/2)=1.0')
xr3 = solve('abs(1+x+x^2/2+x^3/6)=1.0')
xr4 = solve('abs(1+x+x^2/2+x^3/6+x^4/24)=1.0')

ar = linspace(-7,1);
ai = linspace(-4,4);

i=1;
Z = stab_RK1(ar,ai);
[cs,handle] = contour(ar,ai,Z,[1 1]);
set(handle,'LineWidth',3);
axis('square'), axis([-5 3 -4 4]), grid on
hold on

Z = stab_RK2(ar,ai);
[cs,handle] = contour(ar,ai,Z,[1 1]);
set(handle,'LineWidth',3);
axis('square'), axis([-5 3 -4 4]), grid on

Z = stab_RK3(ar,ai);
[cs,handle] = contour(ar,ai,Z,[1 1]);
set(handle,'LineWidth',3);
axis('square'), axis([-5 3 -4 4]), grid on

Z = stab_RK4(ar,ai);
[cs,handle] = contour(ar,ai,Z,[1 1]);
set(handle,'LineWidth',3);
axis('square'), axis([-5 3 -4 4]), grid on

arrow([-4.5 0],[2.5 0]), text(2.5, 0.5,'Re')
arrow([0 -3.5],[0 3.5]), text(0.5, 3.5,'Im')
hold off
%print -deps2 RK.eps