Update cheatsheet.fr.md

12.temporary_ins/08.grad-div-rot/70.combinaisons-of-operators/20.overview/cheatsheet.fr.md

@@ -123,11 +123,13 @@ visible: false
   d'un vecteur $`\overrightarrow{U}`$ **en coordonnées cartésiennes** est :   
   <br>
   **$`\overrightarrow{\Delta}=
-   \left(\begin{array}{l}
-    \dfrac{\partial^2 U_x}}{\partial x^2}+\dfrac{\partial^2 U_x}{\partial y^2}+\dfrac{\partial^2 U_x}{\partial z^2}\\
-    \dfrac{\partial^2 U_y}{\partial x^2}+\dfrac{\partial^2 U_y}{\partial y^2}+\dfrac{\partial^2 U_y}{\partial z^2}\\    
-    \dfrac{\partial^2 U_z}{\partial x^2}+\dfrac{\partial^2 U_z}{\partial y^2}+\dfrac{\partial^2 U_z}{\partial z^2   
-    \end{array}\right)`$**
+   \left(
+   \begin{array}{l}
+    \dfrac{\partial^2 U_x}{\partial x^2} + \dfrac{\partial^2 U_x}{\partial y^2} + \dfrac{\partial^2 U_x}{\partial z^2}\\
+    \dfrac{\partial^2 U_y}{\partial x^2} + \dfrac{\partial^2 U_y}{\partial y^2} + \dfrac{\partial^2 U_y}{\partial z^2}\\    
+    \dfrac{\partial^2 U_z}{\partial x^2} + \dfrac{\partial^2 U_z}{\partial y^2} + \dfrac{\partial^2 U_z}{\partial z^2   
+    \end{array}
+   \right)`$**
 
 <br>
 
@@ -354,6 +356,11 @@ constitue la **définition de l'opérateur laplacien vectoriel** :
 **$`\large{\overrightarrow{\Delta}=\overrightarrow{grad}\big(div\;\overrightarrow{U}\big)
 -\overrightarrow{rot}\big(\overrightarrow{rot}\,\overrightarrow{U}\big)}`$**
 
+<br>
+
+----------------------------------
+
+<br>
 
 ##### 4 - Relation entre les propriétés locales d'un champ vectoriel et sa propagation