Thank you for your comment. I tried to divide and subtract. The problem is the term in the middle: (y' - eps*x') vs. (x' + eps*y')
It makes the situation even worse - I did not succeed in finding a simplified pattern.
The complex notation in my first post has been derived by simply...
What is the function corresponding to this ODE:
http://home.arcor.de/luag/math/dgl.jpg
In complex notation it obviously shows up like this:
a * z''(t) + b * |z'(t)| * z'(t) + c = 0;
The numerical solution shows a graph resembling to a cycloid.
Thanks for any help!
Tom