Update cheatsheet.fr.md

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

@@ -485,7 +485,12 @@ $`\boldsymbol{\mathbf{\cdot\big(-\,R\,\overrightarrow{e_{\rho}}\,+\,z_M\,\overri
 *  L'ensemble des points $`P`$ constituant la spire, de coordonnées  $`P=(R,\,\varphi_M,\,0)`$, s'obtient 
    en faisant varier *$`\varphi_P`$ entre $`0`$ et $`2\pi`$*.   
   <br>
-   **$`\boldsymbol{\mathbf{\displaystyle E_M=\int_{\varphi = 0}^{2\pi}\dfrac{\dens^{1D}}{4\pi\epsilon_0}\cdot\dfrac{R\,z_M}{d^2}\,d\varphi}}`$**
+   **$`\boldsymbol{\mathbf{E_M}}`$**
+   *$`\displaystyle\boldsymbol{\mathbf{\;=\int_{\varphi = 0}^{2\pi}\dfrac{\dens^{1D}}{4\pi\epsilon_0}\cdot\dfrac{R\,z_M}{d^2}\,d\varphi}}`$*   
+   <br>
+   $`\displaystyle\hspace{2.3cm}=\dfrac{\dens^{1D}}{4\pi\epsilon_0}\cdot\dfrac{R\,z_M}{d^2}\;\int_{\varphi = 0}^{2\pi}\,d\varphi`$   
+   <br>
+   **$`\boldsymbol{\mathbf{\hspace{2.3cm}=\dfrac{\dens^{1D}}{2\epsilon_0}\cdot\dfrac{R\,z_M}{d^2}}}`$**
 
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