I remember this system. I do not know what you intend by ‘chaotic trajectory’ here.
If you want to plot the derivative of ‘k’ with respect to time as a function of the derivatve of ‘y’ with respect to time, this works:
for k = 1:numel(t)
ddt(k,:) = ODEfcn(t(k),y(k,:),a); % Calculate Derivatives From Solved Values & ‘ODEfcn’
end
figure
plot(ddt(:,1), ddt(:,2))
grid
axis equal
xlabel('$\frac{dy(t)}{dt}$', 'Interpreter','latex')
ylabel('$\frac{dk(t)}{dt}$', 'Interpreter','latex')
The integrated functions themselves are given by ‘y(:,1)’ for ‘y’, and ‘y(:,2)’ for ‘k’ (remembering those from your earlier Question).
