Update cheatsheet.fr.md

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

@@ -508,24 +508,14 @@ $`\forall \alpha \in \mathbb{R}\;,\,`$ **$`\large{exp{\,\alpha} = cos \,\alpha +
   * $`\underline{A}=A\,e^{\,i\,\varphi}`$ : amplitude complexe.
   * $`\underline{A}^{\ast}=A\,e^{\,-i\,\varphi}`$ : amplitude complexe conjuguée.   
   <br>
-  $`\begin{array}
+  $`\begin{align}
       \large{\mathbf{\color{brown}{\quad \sqrt{\underline{A}\,\underline{A}^{\ast}}}}} &= \sqrt{A\,e^{\,i\,\varphi}\times A\,e^{\,-i\,\varphi}}\\  
   \\
   &= \sqrt{A^2\,e^{\,i\,\varphi}\,e^{\,-i\,\varphi}} = \sqrt{A^2\,e^{\,(i-i)\,\varphi}}\\
   \\
   &= \sqrt{A^2\,e^0}=\sqrt{A^2} = \vert\,A\,\vert^2\\
   \\
-  \large{\mathbf{\color{brown}{&= A^2}}}\end{array}`$
-
-  <br>
-  $`\begin{array}
-      \large{\mathbf{\color{brown}{\quad \sqrt{\underline{A}\,\underline{A}^{\ast}}}}} &= \sqrt{A\,e^{\,i\,\varphi}\times A\,e^{\,-i\,\varphi}}\\  
-  \\
-  &= \sqrt{A^2\,e^{\,i\,\varphi}\,e^{\,-i\,\varphi}} = \sqrt{A^2\,e^{\,(i-i)\,\varphi}}\\
-  \\
-  &= \sqrt{A^2\,e^0}=\sqrt{A^2} = \vert\,A\,\vert^2\\
-  \\
-  &\large{\mathbf{\color{brown}{= A^2}}}\end{array}`$
+  &\large{\mathbf{\color{brown}{= A^2}}}\end{align}`$