# Tag Info

You want a numerical solution, but this might help you check your computed results. If $a$ satisfies the ODE, you know $e^{a(t)}a'(t) = f(t)$. Integrating you get \begin{align} \int_0^t\, f(\tau)\, d\tau &= \int_0^t e^{a(\tau)}a'(\tau)\, d\tau \\ &= \int_{a(0)}^{a(t)} e^a da \\ &= e^{a(t)} - e^{a(0)}. \end{align}