Update cheatsheet.fr.md

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

@@ -70,14 +70,14 @@ PRINCIPALES COMBINAISONS
       * coordonnées cylindriques $`(\rho\,,\,\varphi\,,\,z)`$ :   
         <br>
        $`\Delta\,\phi=\dfrac{1}{\rho}\cdot\dfrac{\partial}{\partial \rho}\left(\rho\,\dfrac{\partial \phi}{\partial \rho}\right)`$
-        $`+\dfrac{1}{\rho^2}\cdot\dfrac{\partial^2 \phi}{\partial \varphi^2}`$
-        $`+\dfrac{\partial^2 \phi}{\partial z^2}`$   
+        $`\;+\;\dfrac{1}{\rho^2}\cdot\dfrac{\partial^2 \phi}{\partial \varphi^2}`$
+        $`\;+\;\dfrac{\partial^2 \phi}{\partial z^2}`$   
        <br>
       * coordonnées sphérique $`(r\,,\,\theta\,,\,\varphi)`$ :   
         <br>
        $`\Delta\,\phi=\dfrac{1}{r}\cdot\dfrac{\partial^2}{\partial r^2}(r\phi)`$
-       $`+\dfrac{1}{r^2\,\sin\theta}\cdot\dfrac{\partial}{\partial \theta}\left(\sin\theta\dfrac{\partial \phi}{\partial \theta}\right)`$
-       $`+\dfrac{1}{r^2\,\sin^2\theta}\cdot\dfrac{\partial^2 \phi}{\partial \varphi^2}`$
+       $`\;+\;\dfrac{1}{r^2\,\sin\theta}\cdot\dfrac{\partial}{\partial \theta}\left(\sin\theta\dfrac{\partial \phi}{\partial \theta}\right)`$
+       $`\;+\;\dfrac{1}{r^2\,\sin^2\theta}\cdot\dfrac{\partial^2 \phi}{\partial \varphi^2}`$
 
 
    ---