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01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md

@@ -205,10 +205,11 @@ propagation of the light (from the object towards the refracting surface)
 ! The direction of the curvature does not presume the convergent or divergent character
 ! of the diopter. It also depends on the refractive index values on each side of the spherical 
 ! refracting surface. look at what happens to the incident ray parallel to the optical axis 
-in Figures 6 and 7, and 8 and 9, and review NOTE 1.
+in Figures 3 and 4, and 5 and 6 below, and review NOTE 1.
 !
 
 
+
 #### Non stigmatism of spherical refracting surfaces
 
 Ray tracing study of a **spherical refracting surface** :