Hello I am sorry for the inconvenient caused and I wish to apologise in advance for my language (I am not a native English speaker).
Here is an exercise I have been trying to do but I guess I am missing something out.
Wording: Let's denote $F$ a differentiable function $(F'= f)$.
Express $F(t)$ $\in $ $[0,T]$, in integral form depending on $f$ and $F(0)$.
Deduct that we can approximate the trajectory $ t -> F(t)$ using this scheme:
$F^n$ $(t_{i+1})$ $=$ $F^n(t_i)$ + $f(t_i)\Delta $$t_{i+1}$
$F^n(0) = F(0)$
Thank you very much for your help,