Problems(discontinuous condition) in Rkfixed

RONG XU wrote: I want to put an Odesolver into a program, so I use rkfixed, but it is not working if I add the 'if statement' \Anyone one know how to solve this? Thanks! Rong

1) Send please the Mathcad file too.

2) We can use the odesolve function in a program to by a creating a user function f(...):= odesolve(...) and by colling this function f(...) in the program.