Update cheatsheet.fr.md

12.temporary_ins/08.grad-div-rot/20.div/20.overview/cheatsheet.fr.md

@@ -32,7 +32,7 @@ div\,\overrightarrow{X}}`$**$`\mathbf{\;=\dfrac{d\Phi_X}{d\tau}}`$**$`\;\mathbf{
 ##### Expression de la divergence en coordonnées sphériques
 
 **$`\boldsymbol{\mathbf{\begin{align}
-div\,\overrightarrow{X}\color{black}{\;=\dfrac{d\Phi_X}{d\tau}}\,= &\dfrac{1}{r^2}\;\dfrac{\partial\,(r^2\,X_r}{\partial\,r}\\
+div\,\overrightarrow{X}\color{grey{\;=\dfrac{d\Phi_X}{d\tau}}\,= &\dfrac{1}{r^2}\;\dfrac{\partial\,(r^2\,X_r}{\partial\,r}\\
 \\
 & \quad\quad + \dfrac{1}{r\,sin\,\theta}\;\dfrac{\partial\,(sin\,\theta\,X_{\theta})}{\partial\,\theta}\\
 \\
@@ -41,7 +41,7 @@ div\,\overrightarrow{X}\color{black}{\;=\dfrac{d\Phi_X}{d\tau}}\,= &\dfrac{1}{r^
 <br>
 
 **$`\mathbf{\boldsymbol{\begin{align}
-div\,\overrightarrow{X}\color{black}{\;=\dfrac{d\Phi_X}{d\tau}}\,= &\dfrac{1}{r^2}\;\dfrac{\partial\,(r^2\,X_r}{\partial\,r}\\
+div\,\overrightarrow{X}\color{gray}{\;=\dfrac{d\Phi_X}{d\tau}}\,= &\dfrac{1}{r^2}\;\dfrac{\partial\,(r^2\,X_r}{\partial\,r}\\
 & \quad\quad + \dfrac{1}{r\,sin\,\theta}\;\dfrac{\partial\,(sin\,\theta\,X_{\theta})}{\partial\,\theta}\\
 & \quad\quad\quad\quad + \dfrac{1}{r\,sin\,\theta}\;\dfrac{\partial\,X_{\varphi}}{\partial\,\varphi}\end{align}}}`$**