I must solving a Kepler's problem (for elliptical orbit, for Earth) with RungeKutta 4th methods in MATLAB, but I don't know what is my differential equation and how I can solving it, what I must put it in differential equation for initial value.
For examples when I change a steps I must get where will be a Earth on his orbit.
And for last value I must get the correct value for period of Earth, 365.24 days, and position of Earth return in started position.
