diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/05.classical-mechanics/vector-analysis/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/05.classical-mechanics/vector-analysis/textbook.fr.md
index 42ce04b68..2acb7c1e6 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/05.classical-mechanics/vector-analysis/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/05.classical-mechanics/vector-analysis/textbook.fr.md
@@ -626,8 +626,8 @@ $`= \left|\left|d\overrightarrow{OM}(t)\right|\right|\cdot d\Psi`$.
 Ainsi, la différentielle du vecteur $`d\left(\overrightarrow{OM}(t)\right)`$
 s'écrit de la manière suivante :
 
-$`d\left(\overrightarrow{OM}(t)\right)=d\left|\left|\overrightarrow{OM}(t))_{\perp}\right|\right|
-\cdot \overrightarrow{e_{||}\,+\,\left|\left|\overrightarrow{OM}(t))_{\perp}\right|\right|
+$`d\left(\overrightarrow{OM}(t)\right)=d\left|\left|\overrightarrow{OM}(t)_{\perp}\right|\right|
+\cdot \overrightarrow{e_{||}}\,+\,\left|\left|\overrightarrow{OM}(t)_{\perp}\right|\right|
 \cdot d\Psi\cdot\overrightarrow{e_{perp}}`$