diff --git a/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md b/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md
index 84745f6db..53e931b64 100644
--- a/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md
+++ b/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md
@@ -186,13 +186,13 @@ ES : sistema de coordenadas cartesianas   <br>
 FR : système de coordonnées cartésiennes   <br>
 EN : Cartesian coordinate system
 
-$`\nabla = \vec{e_x}\,\dfrac{\partial}{\partial x}+\vec{e_y}\,\dfrac{\partial}{\partial y}`$   <br>
-+\vec{e_z}\,\dfrac{\partial}{\partial z}   <br>
+$`\nabla = \vec{e_x}\,\dfrac{\partial}{\partial x}+\vec{e_y}\,\dfrac{\partial}{\partial y}
++\vec{e_z}\,\dfrac{\partial}{\partial z} `$   <br>
 ES : operador nabla   <br>
 FR : opérateur nabla   <br>
 EN : nabla operator
 
-$\vec{grad\;f}=\nabla\;f`$, $`\vec{\nabla\;f`}`$ better, no?   <br>
+$`\vec{grad\;f}=\nabla\;f`$, $`\vec{\nabla\;f`}`$ better, no?   <br>
 ES : gradiente   <br>
 FR : gradient   <br>
 EN : gradient