(48G 49G 50G) Runge-Kutta Diff Eqn solver

[Werner]

I tried it ;-)
It helps if you know that equations are really stored as programs.

As for RKF: it works if you store your program in a variable. Since it is already in EQ, that's what I used. So, for the above problem:

0. 't' STO ( t0 )
[ 1000. 0. ] 'U' STO ( U0 )
{ t U EQ }
0.001 (accepting default stepsize )
3. (or anything, tn)
RKF

Cheers, Werner