Update cheatsheet.fr.md

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

@@ -1072,9 +1072,10 @@ $`\;\;+\dfrac{\Delta A}{2}\left[cos\left(\varphi_m+\dfrac{\Delta\varphi}{2}\righ
 $`\;=A_m\left[\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} - sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right.`$
 $`\hspace{1.3cm} + \left.\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right]`$
 $`\hspace{0.6cm}+\dfrac{\Delta A}{2}\left[\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right.`$
-$`\hspace{1.3cm} - \left.\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right]`$
+$`\hspace{1.3cm} - \left.\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right]`$   
 <br>
-$`\;=A_m\left[\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} - sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right.\right.`$
+$`\require{cancel}\;=A_m\left[\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} - \color{blue}{
+      \xcancel{sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}}sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}}}\right.\right.`$
 $`\hspace{1.3cm} + \left.\left.cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right]`$
 $`\hspace{0.6cm}+\dfrac{\Delta A}{2}\left[\left(cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} + sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right.\right.`$
 $`\hspace{1.3cm} - \left.\left.cos\,\varphi_m\;cos\,\dfrac{\Delta\varphi}{2} - sin\,\varphi_m\;sin\,\dfrac{\Delta\varphi}{2}\right)\right]`$