Update cheatsheet.fr.md

12.temporary_ins/08.conservative-vector-fields/20.conservative-vector-fields-properties/20.overview/cheatsheet.fr.md

@@ -446,11 +446,11 @@ $`\color{brown}{\mathbf{
 
 ##### Expression du gradient en coordonnées cartésiennes
 
-$`\left.\begin{align}
+$`\left.\begin{array}{l}
 dl_x=dx \Longrightarrow \dfrac{\partial x}{\partial l_x}=1\\
 dl_y=dy \Longrightarrow \dfrac{\partial y}{\partial l_y}=1\\
 dl_z=dz \Longrightarrow \dfrac{\partial z}{\partial l_z}=1\\
-\end{align}\right\}`$
+\end{array}\right\}`$
 $`\Longrightarrow\color{brown}{\mathbf{
 \overrightarrow{grad}\,\phi=
 \dfrac{\partial \phi}{\partial x}\,\overrightarrow{e_x}
@@ -461,11 +461,11 @@ $`\Longrightarrow\color{brown}{\mathbf{
 
 ##### Expression du gradient en coordonnées cylindriques
 
-$`\left.\begin{align}
+$`\left.\begin{array}{l}
 dl_{\rho}=d\rho\Longrightarrow \dfrac{\partial \rho}{\partial l_{\rho}}=1\\
 dl_{\varphi}=\rho\,d{\varphi} \Longrightarrow \dfrac{\partial \varphi}{\partial l_{\varphi}}=\dfrac{1}{\rho}\\
 dl_z=dz \Longrightarrow \dfrac{\partial z}{\partial l_z}=1\\
-\end{align}\right\}`$
+\end{array}\right\}`$
 $`\Longrightarrow\color{brown}{\mathbf{
 \overrightarrow{grad}\,\phi=
 \dfrac{\partial \phi}{\partial \rho}\,\overrightarrow{e_{\rho}}
@@ -475,11 +475,11 @@ $`\Longrightarrow\color{brown}{\mathbf{
 
 ##### Expression du gradient en coordonnées sphériques
 
-$`\left.\begin{align}
+$`\left.\begin{array}{l}
 dl_r=dr\Longrightarrow \dfrac{\partial r}{\partial l_r}=1\\
 dl_{\theta}=r\,d{\theta} \Longrightarrow \dfrac{\partial r}{\partial l_r}=\dfrac{1}{r}\\
-dl_{\varphi}=r\,\sin\theta\,d\varphi \Longrightarrow \dfrac{\partial l_{\varphi}}{\partial l_{\varphi}}=\dfrac{1}{r\,\sin\theta}\\
-\end{align}\right\}`$
+dl_{\varphi}=r\,\sin\theta\,d\varphi \Longrightarrow \dfrac{\partial \varphi}{\partial l_{\varphi}}=\dfrac{1}{r\,\sin\theta}\\
+\end{array}\right\}`$
 $`\Longrightarrow\color{brown}{\mathbf{
 \overrightarrow{grad}\,\phi=
 \dfrac{\partial \phi}{\partial r}\,\overrightarrow{e_r}