Update cheatsheet.fr.md

12.temporary_ins/10.electrostatics-vacuum/20.causes-stationary-electric-field/20.overview/cheatsheet.fr.md

@@ -762,14 +762,14 @@ figure à faire
 
 * L'intégration sur la variable $`d\varphi`$ donne :   
   <br>
-  $`\mathbf{\boldsymbol{E_M}}`$ 
-  $`\;=\dfrac{\dens^{2D}\,z_M}{4\pi\,\epsilon_0}
+  *$`\mathbf{\boldsymbol{E_M}}`$* 
+  $`\displaystyle\;=\dfrac{\dens^{2D}\,z_M}{4\pi\,\epsilon_0}
   \times
   \int_{\varphi=0}^{2\pi} d\varhi 
   \times
   \int_{\rho=0}^{R} \rho\,(\rho^2+z_M^2)^{\,-3/2}\,d\rho`$   
   <br>
-  $`\boldsymbol{\mathbf{\hspace{1.5 cm}=\dfrac{\dens^{2D}\,z_M}{2\,\epsilon_0}\times\int_{\rho=0}^{R} \rho\,(\rho^2+z_M^2)^{\,-3/2}\,d\rho}}`$
+  *$`\displaystyle\boldsymbol{\mathbf{\hspace{1.5 cm}=\dfrac{\dens^{2D}\,z_M}{2\,\epsilon_0}\times\int_{\rho=0}^{R} \rho\,(\rho^2+z_M^2)^{\,-3/2}\,d\rho}}`$*
 
 * L'intégration sur la variable $`d\rho`$ donne :