diff --git a/01.curriculum/01.physics-chemistry-biology/04.Niv4/04.electromagnetism/02.electromagnetic-waves-vacuum/02.electromagnetic-waves-vacuum-main/textbook.fr.md b/01.curriculum/01.physics-chemistry-biology/04.Niv4/04.electromagnetism/02.electromagnetic-waves-vacuum/02.electromagnetic-waves-vacuum-main/textbook.fr.md
index 750449f43..3cdb174c5 100644
--- a/01.curriculum/01.physics-chemistry-biology/04.Niv4/04.electromagnetism/02.electromagnetic-waves-vacuum/02.electromagnetic-waves-vacuum-main/textbook.fr.md
+++ b/01.curriculum/01.physics-chemistry-biology/04.Niv4/04.electromagnetism/02.electromagnetic-waves-vacuum/02.electromagnetic-waves-vacuum-main/textbook.fr.md
@@ -49,6 +49,7 @@ $`\overrightarrow{rot} \, \left( \overrightarrow{rot}\,\overrightarrow{E} \right
$`\overrightarrow{rot} \, \left( \overrightarrow{rot}\,\overrightarrow{E} \right)
=-\mu_0\;\dfrac{\partial \overrightarrow{j}}{\partial t} +
-\mu_0 \epsilon_0 \;\dfrac{\partial^2 \overrightarrow{E}}{\partial t^2}`$
+\mu_0 \epsilon_0 \;\dfrac{\partial^2 \overrightarrow{E}}{\partial t^2}`$
+
* $`\overrightarrow{grad} \left( div \; \overrightarrow{E} \right) = \overrightarrow{grad} \left( \dfrac{\rho}{\epsilon_O} \right)`$