 \left( \frac{v_{\rm T} \sin \alpha_{\rm T} + a \dot{\psi}}{ v_{\rm T} \cos \alpha_{\rm T}} \right) - \delta_{\rm F} \\
% \alpha_{\rm R} &=& \arctan \left( \frac{v_{\rm T} \sin \alpha_{\rm T} - b \dot{\psi}}{ v_{\rm T} \cos \alpha_{\rm T}} \right) - \delta_{\rm R}
% \label{eq:slipanglesnewvariables}
% \end{eqnarray}
% </p>
% </html>

VF_t    = diff(PFO_t,t);
VR_t    = diff(PRO_t,t);

VF      = formula(subs(VF_t,symfunVariables,symVariables));
VR      = formula(subs(VR_t,symfunVariables,symVariables));

VF_a