Update cheatsheet.fr.md

12.temporary_ins/90.electromagnetism-in-vacuum/20.electromagnetic-waves-vacuum/20.overview/cheatsheet.fr.md

@@ -172,11 +172,10 @@ puis d'une onde plane progressive monochromatique (OPPM).
     <br>
     $`\Longrightarrow\left\{
     \begin{align}
-    &\left|\begin{align}
     \dfrac{\partial E_z}{\partial y}-\dfrac{\partial E_y}{\partial z}=-\dfrac{\partial B_x}{\partial t}\\
     \dfrac{\partial E_x}{\partial z}-\dfrac{\partial E_z}{\partial x}=-\dfrac{\partial B_y}{\partial t}\\
-    \dfrac{\partial E_y}{\partial x}-\dfrac{\partial E_x}{\partial y}=-\dfrac{\partial B_z}{\partial t}
-    \end{align}\right.\\
+    \dfrac{\partial E_y}{\partial x}-\dfrac{\partial E_x}{\partial y}=-\dfrac{\partial B_z}{\partial t}\\
+    \\
     \dfrac{\partial E_z}{\partial y}=\dfrac{\partial E_y}{\partial z}=\dfrac{\partial E_x}{\partial z}\\
     \quad =\dfrac{\partial E_z}{\partial x}=\dfrac{\partial E_y}{\partial x}=\dfrac{\partial E_x}{\partial y}=0
     \end{align}\right.`$