Update cheatsheet.fr.md

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

@@ -62,7 +62,7 @@ $`\newcommand{\ddpt}[1]{\overset{\large\bullet\bullet}{#1}}`$
 
 $`\color{brown}{\mathbf{U(x,t)}}\; = U_1(x,t) + U_2(x,t)`$   
 <br>
-$`\begin{align} \quad &=A\;\big[\,cos(\underbrace{kx - \omega t}_{\text{  posons }\\ kx - \omega t \,=\, \alpha} + \varphi_1) + cos(\underbrace{kx - \omega t}_{=\; \alpha} + \varphi_1)\,\big]
+$`\begin{align} \quad &=A\;\big[\,cos(\underbrace{kx - \omega t}_{\color{blue}{\text{  posons }\\ kx - \omega t \,=\, \alpha}} + \varphi_1) + cos(\underbrace{kx - \omega t}_{\color{blue}{=\; \alpha}} + \varphi_1)\,\big]
 &\\
 &=A\;\big[\,cos\Big(\alpha + \dfrac{\varphi_1+\varphi_1}{2} + \dfrac{\varphi_2-\varphi_2}{2}\Big) \\
 &\quad\quad\quad\quad + \,cos\Big(\alpha + \dfrac{\varphi_2+\varphi_2}{2} + \dfrac{\varphi_1-\varphi_1}{2}\Big)\,\Big]\\
@@ -79,7 +79,7 @@ $`\begin{align} \quad &=A\;\big[\,cos(\underbrace{kx - \omega t}_{\text{  posons
 &=2\,A\cdot cos(\alpha ')\,cos\Big(\dfrac{\varphi_1-\varphi_2}{2}\Big)
 \end{align}`$   
 <br>
-$`\quad=\color{blue}{\underbrace{\color{brown}{2\,A\cdot cos\Big(\dfrac{\varphi_1-\varphi_2}{2}\Big)}}_{\text{amplitude de l'onde résultante}}} \color{brown}{\cdot cos\Big(}\color{blue}{\underbrace{\color{brown}{kx - \omega t + \dfrac{\varphi_1+\varphi_2}{2}}}_{\text{pulsation }\omega\text{ inchangée}}}\color{brown}{\Big)}`$**
+$`\quad\boldsymbol{\mathbf{=\color{blue}{\underbrace{\color{brown}{2\,A\cdot cos\Big(\dfrac{\varphi_1-\varphi_2}{2}\Big)}}_{\text{amplitude de l'onde résultante}}} \color{brown}{\cdot cos\Big(}\color{blue}{\underbrace{\color{brown}{kx - \omega t + \dfrac{\varphi_1+\varphi_2}{2}}}_{\text{pulsation }\omega\text{ inchangée}}}\color{brown}{\Big)}}}`$