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 9bbded7cf..9aa63765f 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
@@ -14,7 +14,7 @@ seront là pour être utilisés, ou remaniés et modifiés. -->
 
 $`div \overrightarrow{E} = \dfrac{\rho}{\epsilon_0}`$
 
-$`\overrightarrow{rot} \;\overrightarrow{E} = 0`$
+$`\overrightarrow{rot} \;\overrightarrow{E} = -\dfrac{\partial \overrightarrow{B}}{\partial t}`$
 
 $`div \overrightarrow{B} = 0`$