Update textbook.fr.md

01.curriculum/01.physics-chemistry-biology/04.Niv4/04.electromagnetism/02.electromagnetic-waves-vacuum/02.electromagnetic-waves-vacuum-main/textbook.fr.md

@@ -29,3 +29,9 @@ je peux écrire :
 
 $`\overrightarrow{rot} \, \left( \overrightarrow{rot}\,\overrightarrow{E} \right)=
 -\dfrac{\partial}{\partial t} \,\left(\overrightarrow{rot}\overrightarrow{B}\right)`$
+
+$`\overrightarrow{rot} \, \left( \overrightarrow{rot}\,\overrightarrow{E} \right)=
+-\dfrac{\partial}{\partial t} \,\left(\mu_0\;\overrightarrow{j} +
+\mu_0 \epsilon_0 \;\dfrac{\partial \overrightarrow{j}}{\partial t}\right)`$
+
+