Update cheatsheet.fr.md

12.temporary_ins/69.waves/30.n3/20.overview/cheatsheet.fr.md

@@ -1042,10 +1042,14 @@ _ figure erronée à refaire_
   **$`\large{\boldsymbol{\mathbf{\Lambda = \dfrac{\lambda_1}{sin\,\theta_1}}}}\quad`$** 
   et *$`\quad\large{\boldsymbol{\mathbf{\Lambda = \dfrac{\lambda_2}{sin\,\theta_2}}}}`$*.   
   <br>
-  $`\left.\begin{align}
+  $`\begin{align}
+   \left.\begin{align}
    &\Lambda = \dfrac{\lambda_1}{sin\,\theta_1}\\
    &\Lambda = \dfrac{\lambda_2}{sin\,\theta_2}
-   \end{align}\right\}\Longrightarrow\;\dfrac{sin\,\theta_1}{\mathscr{v}_1\,T}=\dfrac{sin\,\theta_2}{\mathscr{v}_2\,T}`$
+   \end{align}\right\}&\Longrightarrow\;\dfrac{sin\,\theta_1}{\lambda_1}=\dfrac{sin\,\theta_2}{\lamnda_2}\\
+   &\Longrightarrow\;\dfrac{sin\,\theta_1}{\mathscr{v}_1\,T}=\dfrac{sin\,\theta_2}{\mathscr{v}_2\,T}\\
+   &\Longrightarrow\;\dfrac{sin\,\theta_1}{\mathscr{v}_1}=\dfrac{sin\,\theta_2}{\mathscr{v}_2}
+   \end{align}`$