Update cheatsheet.fr.md

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

@@ -344,14 +344,6 @@ $`\forall \alpha \in \mathbb{R}\;,\,`$ **$`\large{exp{\,\alpha} = cos \,\alpha +
    * soit en **notation complexe** :    
      1D : **$`\quad\large{\boldsymbol{\mathbf{\underline{U}(x,t)=A\cdot e^{\,i\,(\omega t - k x + \varphi)}}}}`$**   
      <br>   
-     3D : $`\begin{align}
-               \mathbf{\color{brown}{\quad\underline{U}(x,t)&=A\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r} + \varphi)}  }}\\
-               &=A\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r})}\cdot  e^{\,i\varphi)}\\
-               &=A\cdot  e^{\,i\varphi)}\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r})}\\
-               &=\mathbf{\color{brown}{\underline{A}\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r})}  }}\\
-               &\quad\quad\text{avec }\mathbf{\color{blue}{\underline{A}=A\; e^{\,i\varphi} }}\\
-               &\quad\quad\quad\color{blue}{\text{amplitude complexe}}\end{align}`$
-
      3D : **$`\quad\boldsymbol{\mathbf{\large{\underline{U}(\vec{r},t) &=A\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r} + \varphi)}}}}`$**    
             $`\quad\quad\quad\ =A\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r})}\cdot  e^{\,i\varphi}`$     
             $`\quad\quad\quad\ =A\cdot  e^{\,i\varphi)}\cdot e^{\,i\,(\omega t - \vec{k}\cdot\vec{r})}`$