Update cheatsheet.fr.md

12.temporary_ins/69.waves/30.n3/20.overview/cheatsheet.fr.md

@@ -1703,18 +1703,18 @@ $`\quad\quad \;\; = \cdots`$
 
  * L'**onde réelle** est la *partie réelle de l'onde complexe* :    
   <br>
-  $`U(\overrightarrow{r},t)\,=\,\mathbb{R}e\big(\underline{U}(\overrightarrow{r},t))`$   
+  $`U(\overrightarrow{r},t)\,=\,\mathscr{R}e\big(\underline{U}(\overrightarrow{r},t))`$   
   <br>
   $`\begin{array}\quad = &+\,2\,A_{moy}\,cos(\theta_{12})\; e^{\,i\,\theta_{moy}}\\
    &-\,2i\,\Delta A_{1-2}\,sin(\theta_{12})\; e^{\,i\,\theta_{moy}}\end{array}`$   
   <br>
-  $`\color{blue}{\scriptsize{exp(ia)\,=\, cos\,a\,+\,i\, sin\,a}}`$  
+  $`\color{blue}{\scriptsize{\text{Utilisons }\;exp(ia)\,=\, cos\,a\,+\,i\, sin\,a}}`$  
   <br>   
-  $`\begin{array}\quad = &\mathbb{R}e \big[\,2\,A_{moy}\,cos(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy}})\\
-   &-\,2i\,\Delta A_{1-2}\,sin(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy}})\big]\end{array}`$  
+  $`\begin{array}\quad = &\mathscr{R}e \big[\,2\,A_{moy}\,cos(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy})\\
+   &-\,2i\,\Delta A_{1-2}\,sin(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy})\big]\end{array}`$  
   <br>
-  $`\begin{array}\quad = &2\times\mathbb{R}e \big[\,A_{moy}\,cos(\theta_{12})\;cos\,\theta_{moy}\,-\,sin\,\theta_{moy}})\\
-   &-\,2i\,\Delta A_{1-2}\,sin(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy}})\end{array}`$    
+  $`\begin{array}\quad = &2\times\mathscr{R}e \big[\,A_{moy}\,cos(\theta_{12})\;cos\,\theta_{moy}\,-\,sin\,\theta_{moy})\\
+   &-\,2i\,\Delta A_{1-2}\,sin(\theta_{12})\;(cos\,\theta_{moy}\,+\,isin\,\theta_{moy})\end{array}`$