Update textbook.en.md

10.brainstorming-innovative-courses/intercambio-curso-electromagnetismo/textbook.en.md

@@ -319,7 +319,7 @@ S.I. : $`A \cdot m`$
 
 EN : $`\vec{dH_M}=\dfrac{1}{4\pi}\cdot\dfrac{I\cdot\vec{dl}_P\times\vec{PM}}{||\vec{PM}||^3}`$
 
-$`\vec{dH_M}`$ : magnetic field vector (S.I. unit : $À\cdot m^{-1}`$ or $`A/m`$)
+$`\vec{dH_M}`$ : magnetic field vector (S.I. unit : $`A\cdot m^{-1}`$ or $`A/m`$)
 $`\vec{dB_M}`$ : flux density or magnetic field induction vector (S.I. unit : $`T`$)
 
 $`\vec{dH}=\dfrac{1}{4\pi}\cdot\dfrac{I\cdot\vec{dl}\times\vec{r}}{r^3}=\dfrac{1}{4\pi}\cdot\dfrac{I\cdot\vec{dl}\times\vec{e_r}}{r^2}`$