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 45bc89d4e..b19e24417 100644
--- a/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md
+++ b/10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md
@@ -197,14 +197,14 @@ FR : opérateur nabla   <br>
 EN : nabla operator
 
 
-$`\Deltaf = div\,\overrightarrow{grad}\f `$, $`\Deltaf = \overrightarrow{\nabla}\cdot\overrightarrow{\nabla}\,f `$
+$`\Delta\,f = div\,\overrightarrow{grad} \,f `$, $`\Delta\,f = \overrightarrow{\nabla}\cdot\overrightarrow{\nabla}\,f `$  <br>
 ES : operador laplaciana escalar, laplaciana escalar, laplaciana de un campo escalar   <br>
 FR : opérateur laplacien scalaire, laplacien scalaire, laplacien d'un champ scalaire  <br>
-EN : laplacian operator, laplacian of a scalar field
-ES :
-FR : en coordonnées cartésiennes orthonormées :
-EN : in orthonormal Cartesian coordinate :
-$ \Delta = \dfrac{\partial^2}{\partial x^2}+\dfrac{\partial^2}{\partial y^2}+\dfrac{\partial^2}{\partial z^2}`$
+EN : laplacian operator, laplacian of a scalar field  <br>
+ES : en coordenadas cartesianas ortonormalas<br>
+FR : en coordonnées cartésiennes orthonormées :  <br>
+EN : in orthonormal Cartesian coordinate :  <br>
+$`\Delta = \dfrac{\partial^2}{\partial x^2}+\dfrac{\partial^2}{\partial y^2}+\dfrac{\partial^2}{\partial z^2}`$
 
 $`\Delta = \overrightarrow{grad} div\,\overrightarrow{U} - \overrightarrow{rot}\,\overrightarrow{rot}\,\overrightarrow{U}`$   <br>
 ES : operador laplaciana vectorial, laplaciana vectorial, laplaciana de un campo vectorial   <br>