diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
index e2c6db9dc..ab8157a4d 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
@@ -227,8 +227,8 @@ http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=121-11-21<br>
 [ES] Tenemos que elegir de forma independiente para cada idioma, entre estas notaciones :<br>
 Nous devons choisir de façon indépendante pour chaque langue, entre ces notations :<br>
 We have to choose independently for each language, between these notations :<br>
-$`\overrightarrow{dA}\quad`$,$`\quad\overrightarrow{dA}^2\quad`$,
-$`\quad\overrightarrow{dS}\quad`$,$`\quad\overrightarrow{dA}^2\quad`$  
+$`\overrightarrow{dA}\quad`$,$`\quad\overrightarrow{d^2A}\quad`$,
+$`\quad\overrightarrow{dS}\quad`$,$`\quad\overrightarrow{d^2S}\quad`$  
 
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