i'm a math student and i do need help about the proof of Runge Kutta Method of 4th order. Especially i need information about how to find the terms k1, k2, k3, k4. There has to be explanations in the proof about four of them, step by step. Otherwise it is not useful for me . Wherever i check, there is such a note like "it is beyond us to show how these terms can be found but we'll explain a little bit". However this is not enough for me. Is there anyone who can help me about finding an advanced proof of 4th order Runge-Kutta?