Update cheatsheet.fr.md

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

@@ -172,20 +172,22 @@ puis d'une onde plane progressive monochromatique (OPPM).
     <br>
     $`\Longrightarrow\left\{
     \begin{align}
-    \dfrac{\partial E_z}{\partial y}-\dfrac{\partial E_y}{\partial z}=-\dfrac{\partial B_x}{\partial t}\\
-    \dfrac{\partial E_x}{\partial z}-\dfrac{\partial E_z}{\partial x}=-\dfrac{\partial B_y}{\partial t}\\
-    \dfrac{\partial E_y}{\partial x}-\dfrac{\partial E_x}{\partial y}=-\dfrac{\partial B_z}{\partial t}\\
+    &\dfrac{\partial E_z}{\partial y}-\dfrac{\partial E_y}{\partial z}=-\dfrac{\partial B_x}{\partial t}\\
+    &\dfrac{\partial E_x}{\partial z}-\dfrac{\partial E_z}{\partial x}=-\dfrac{\partial B_y}{\partial t}\\
+    &\dfrac{\partial E_y}{\partial x}-\dfrac{\partial E_x}{\partial y}=-\dfrac{\partial B_z}{\partial t}\\
     \\
-    \dfrac{\partial E_z}{\partial y}=\dfrac{\partial E_y}{\partial z}=\dfrac{\partial E_x}{\partial z}\\
-    \quad =\dfrac{\partial E_z}{\partial x}=\dfrac{\partial E_y}{\partial x}=\dfrac{\partial E_x}{\partial y}=0
-    \end{align}\right.`$
+    &\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.`$   
+    <br>
+    *$`\Longrightarrow\left\{
+    \begin{align}
+    &dfrac{\partial B_x}{\partial t}=- dfrac{\partial E_y}{\partial z}\\
+    &dfrac{\partial B_y}{\partial t}=- dfrac{\partial E_x}{\partial z}\\
+    &dfrac{\partial B_z}{\partial t}=0
+    \end{align}\right.`$*
 
-\dfrac{\partial E_x}{\partial x}+\dfrac{\partial E_y}{\partial y}
-    +\dfrac{\partial E_z}{\partial z}=0\\
-    \\
-    &\dfrac{\partial E_x}{\partial x}=\dfrac{\partial E_y}{\partial y}=0
-    \end{align}\right\}`$
-    *$`\Longrightarrow\;\dfrac{\partial E_z}{\partial z}=0`$*   
+