Update cheatsheet.fr.md

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

@@ -1045,7 +1045,7 @@ _ figure erronée à refaire_
   $`\left.\begin{align}
    &\Lambda = \dfrac{\lambda_1}{sin\,\theta_1}\\
    &\Lambda = \dfrac{\lambda_2}{sin\,\theta_2}
-   \end{align}\right\}&\Longrightarrow\;\dfrac{sin\,\theta_1}{\lambda_1}=\dfrac{sin\,\theta_2}{\lamnda_2}`$   
+   \end{align}\right\}\Longrightarrow\;\dfrac{sin\,\theta_1}{\lambda_1}=\dfrac{sin\,\theta_2}{\lamnda_2}`$   
    <br>
    $`\hspace{2cm}\Longrightarrow\;\dfrac{sin\,\theta_1}{\mathscr{v}_1\,T}=\dfrac{sin\,\theta_2}{\mathscr{v}_2\,T}`$   
    <br>