ferential equations, so if I give you
    $\theta(0)$ and $\dot\theta(0)$, then you should be able to integrate them
    to obtain $\theta(t)$... right?  Although it is possible, integrating even
    the simplest case ($b = u = 0$) involves elliptic integrals of the first
    kind; there is relatively little intuition to be gained here. </p>

    <p> This is in stark contrast to the case of linear systems, where much of
    our understanding comes from being able to explicitly integrate the
    equations. F