Update cheatsheet.fr.md

10.temporary-m3p2/16.waves/20.n2/10.concept-of-wave-and-wave-phenomena-2/20.overview/cheatsheet.fr.md

@@ -857,8 +857,8 @@ cos\left(\dfrac{(\omega t + \varphi_1^0 - \omega t - \varphi_2^0}{2}\right)`$
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 et tu obtiens :   
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-   **$`\quad\boldsymbol{\mathbf{U(t) = 2\,A\cdot cos\Big(\dfrac{\varphi_1-\varphi_2}{2}\Big)}}`$**   
-   **$`\hspace{2cm}\boldsymbol{\quad \times\; cos\Big(\color{blue}{\underbrace{\color{brown}{\omega t + \dfrac{\varphi_1+\varphi_2}{2}}}_{\text{pulsation }\omega\text{ inchangée}}}\color{brown}{\Big)}}`$**
+**$`\quad\boldsymbol{\mathbf{U(t) = 2\,A\cdot cos\Big(\dfrac{\varphi_1-\varphi_2}{2}\Big)}}`$**   
+**$`\hspace{2cm}\boldsymbol{\quad \times\; cos\Big(\color{blue}{\underbrace{\color{brown}{\omega t + \dfrac{\varphi_1+\varphi_2}{2}}}_{\text{pulsation }\omega\text{ inchangée}}}\color{brown}{\Big)}}`$**
 
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 * Les *phases des deux ondes*, $`\omega t + \varphi_1^0`$ et $`\omega t + \varphi_2^0`$, sont *différentes*.