diff --git a/12.temporary_ins/70.wave-optics/20.diffraction/cheatsheet.fr.md b/12.temporary_ins/70.wave-optics/20.diffraction/cheatsheet.fr.md
index 3e1e26a66..c607be4e1 100644
--- a/12.temporary_ins/70.wave-optics/20.diffraction/cheatsheet.fr.md
+++ b/12.temporary_ins/70.wave-optics/20.diffraction/cheatsheet.fr.md
@@ -213,8 +213,8 @@ $`\displaystyle=\int_{-x_0/2}^{+x_0/2}  e^{\dfrac{i\,2\,\pi\,u_x\,x}{\lambda}}\;
 $`\displaystyle \underline{A}=\dfrac{\lambda}{i\,2\,\pi\,u_x}\left(e^{\dfrac{i\,\pi\,u_x\,x_0}{\lambda}}-\;e^{\dfrac{-i\,\pi\,u_x\,x_0}{\lambda}}\right)`$
 
 $`\displaystyle \underline{A}=-i\; \dfrac{\lambda}{i\,2\,\pi\,u_x}`$
-$`\left[ \left(cos\;\dfrac{\pi\,u_x\,x_0}{\lambda}\right.`$
-$`\left.\;+i\;sin\dfrac{\pi\,u_x\,x_0}{\lambda}\right)\right.`$
+$`\left[ \left(cos\;\dfrac{\pi\,u_x\,x_0}{\lambda}\right.\right.`$
+$`\left.\;+i\;sin\dfrac{\pi\,u_x\,x_0}{\lambda}\right)`$
 $`\left.-\left( cos\;\dfrac{\pi\,u_x\,x_0}{\lambda}-i\;sin\;\dfrac{\pi\,u_x\,x_0}{\lambda}\right)\right]`$
 
 $`\displaystyle \underline{A}=-i\; \dfrac{\lambda}{2\pi,u_x} \left( 2\,sin \;\dfrac{\pi\,u_x\,x_0}{\lambda}\right)`$
@@ -255,8 +255,7 @@ $`=\;sin\,\theta\cdot\overrightarrow{e_x}\;+\;cos\,\theta\cdot\overrightarrow{e_
 
 ainsi l'intensité diffractée à l'infini se réécrit
 
-$`I(\theta)=x_0^2\cdot \dfrac{sin^2\,\left( \dfrac{\pi\,x_0\,sin\,\theta}{\lambda} \right)}`$
-$`\;{\left( \dfrac{\pi\,x_0\,sin\,\theta}{\lambda} \right)^2}`$
+$`I(\theta)=x_0^2\cdot \dfrac{sin^2\,\left( \dfrac{\pi\,x_0\,sin\,\theta}{\lambda} \right)}{\left(\dfrac{\pi\,x_0\,sin\,\theta}{\lambda}\right)^2}`$
 $`\quad=x_0^2\cdot sinc^2\left( \dfrac{\pi\,x_0\,sin\,\theta}{\lambda} \right)`$