n</span>
ddx_Alt_t   = simplify(diff(dx_Alt_t,t));
ddy_Alt_t   = simplify(diff(dy_Alt_t,t));
ddx_Alt     = subs(ddx_Alt_t,symfunVariables,symVariables);
ddy_Alt     = subs(ddy_Alt_t,symfunVariables,symVariables);
</pre><h2 id="8">Slip angles</h2><p>
<p>Using equations \ref{eq:velfront} and \ref{eq:velrear}, the slip angles can be written as</p>
<p>
\begin{eqnarray}
\nonumber \alpha_{\rm F} &=& \arctan \left( \frac{\dot{y} + a \dot{\psi} \cos \psi}{ \dot{x} - a \dot{\psi} \sin \psi} \right) - \left( \delta_{