Update textbook.fr.md

12.temporary_ins/40.classical-mechanics/30.n3/07.coherence/textbook.fr.md

@@ -589,7 +589,11 @@ $`\begin{align}
 \\
 &=\dfrac{d}{dt}\big(\mathscr{l}\;\omega\;\overrightarrow{e_{\theta}}\big)\\
 \\
-&=\underbrace{\dfrac{d\mathscr{l}}{dt}}_{=\,0}\;\omega\;\overrightarrow{e_{\theta}}\;+\;\mathscr{l}\;\dfrac{d\omega}{dt}\;\overrightarrow{e_{\theta}}\;+\;\mathscr{l}\;\omega\;\underbrace{\dfrac{d\overrightarrow{e_{\rho}}}{dt}}_{=\,\omega\,\vec{e_{\theta}}}
+&=\underbrace{\dfrac{d\mathscr{l}}{dt}}_{=\,0}\;\omega\;\overrightarrow{e_{\theta}}\;
++\;\mathscr{l}\;\dfrac{d\omega}{dt}\;\overrightarrow{e_{\theta}}\;
++\;\mathscr{l}\;\omega\;\underbrace{\dfrac{d\overrightarrow{e_{\theta}}}{dt}}_{=\,-\omega\,\vec{e_{\rho}}}\\
+\\
+&=\mathscr{l}\;\dfrac{d\omega}{dt}\;\overrightarrow{e_{\theta}}\;-\;\omega^2\overrightarrow{e_{\rho}}
 \end{align}`$