what is the meaning of type operator :: and module memeber selector :-? the maple help doesn't explain to me..

Dear all, I'm frustrated by some ODE problems. sorry the form is a little bit complex: solution := dsolve([diff(s(t),t) = A - A * rho^((1 - r^(theta * t)) * x) - v, diff(f(t),t)=((c - s(t)) / l) * m + x, diff(h(t),t) = x, f(0) = 0, s(0) = 0, h(0) = 0], numeric); for this problem no closed-form, only numerical solution can be found. I have following questions: (1) why cannot I evaluate the value of f(t) at t=5 by using f(5)? (2) For each fixed x, there are curves s(t), f(t), and h(t). Given s(tau) = c, I want to find f(tau)=?. How can I do that? Do I need to find tau first, then find f(tau)? How?

Dear all, I'm frustrated by some ODE problems. sorry the form is a little bit complex: solution := dsolve([diff(s(t),t) = A - A * rho^((1 - r^(theta * t)) * x) - v, diff(f(t),t)=((c - s(t)) / l) * m + x, diff(h(t),t) = x, f(0) = 0, s(0) = 0, h(0) = 0], numeric); for this problem no closed-form, only numerical solution can be found. I have following questions: (1) why cannot I evaluate the value of f(t) at t=5 by using f(5)? (2) For each fixed x, there are curves s(t), f(t), and h(t). Given s(tau) = c, I want to find f(tau)=?. How can I do that? Do I need to find tau first, then find f(tau)? How?