I'm having the following problem:
1) I define a function using an ordinary differential equation (in the file I use the function l which is simply the identity). Everything seems to work fine.
2) Then I use the previous function to define a new ordinary differential equation (ODE). Now things do not work! In my file I define the function m as m'[x]=l[m[x]], m=1, which should be simply the exponential, but I get the error "NDSolve::ndnum: Encountered non-numerical value for a derivative at x == 0." What happened?
The point is not to get the exponential (I'm working on a more complex example, but have the same issue), but rather to get the graph of the second function m.
Attachment: Untitled-3.nb, URL: ,