Update cheatsheet.en.md

01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/03.optical-systems-vergence/02.optical-systems-vergence-overview/cheatsheet.en.md

@@ -310,7 +310,8 @@ Fig. 14.
 
 * **Emerging ray** (or its extension) = *straight line between impact point and B'*.
 
-![To find the deviation of any incident ray](rayon-incident-quelconque-2.gif)
+![](rayon-incident-quelconque-4.gif)<br>
+Fig. 15.
 
 
 ##### Determining the incident ray corresponding to any emergent ray
@@ -400,7 +401,7 @@ The imager gives an image of an object. The **characterization of imager action*
 or $M_A=\pm\dfrac{ \alpha '}{ \alpha }$, with sign + when erect image, sign - when inverted image.<br><br>
 
 ![](apparent-magnitude-magnifying-glass-1018.gif)<br>
-Fig. 15. In this experiment, the observed object is located at a certain distance from the magnifying glass, as well as the eye of the observer. For these conditions of use, the magnifying glass gives a magnification of +2.5. There are optimum conditions for using the magnifying glass (see chapter "optical instruments").
+Fig. 16. In this experiment, the observed object is located at a certain distance from the magnifying glass, as well as the eye of the observer. For these conditions of use, the magnifying glass gives a magnification of +2.5. There are optimum conditions for using the magnifying glass (see chapter "optical instruments").
 
 !!!! *BE CAREFUL*<br>
 !!!!An apparent angle depends on distance from the object or the image to the nodal point of the observing system (human eye or telephoto lens of a camera for example) $\Longrightarrow$ more accurate definitions of apparent angles will be necessary (see chapter "optical instruments").