{\rm O}}}{\partial \psi} = b \sin \psi {\bf i} - b \cos \psi {\bf j}
    \end{eqnarray}
</p>
</p><pre class="codeinput"><span class="comment">% Generalized forces</span>
Q1 = FF*diff(PFO,x)'    + FR*diff(PRO,x)'    ;
Q2 = FF*diff(PFO,y)'    + FR*diff(PRO,y)'    ;
Q3 = FF*diff(PFO,PSI).' + FR*diff(PRO,PSI).' ;
</pre><p>
<p>Substituting equations</p>
<p>
    \begin{eqnarray}
    \nonumber Q_1 &=& F_{x,{\rm F}} \cos \left( \psi + \delta_{\rm F} \right) - F_{y,{\rm F}} \sin \left( \psi + \delta_{\rm F} \right) 