- 31,528

- 4,631

Then you made mistakes, but if you don't post your working I have no idea where.I tried to do that and I ended up with an equation of the sort of du/dt * C = 0, it was a veeeeery long equation in the beginning but all sines/cosines etc got cancelled in one way or another.

Where C is v/(sqrt(c+2)) if I recall correctly (I dont have the papers infront of me).

Try just differentiating your first equation in post #23 with respect to time and post what you get.