From 7842e96754575a6344b8406ae075e4ddae8e58ee Mon Sep 17 00:00:00 2001 From: Claude Meny Date: Sun, 6 Oct 2019 16:25:44 +0200 Subject: [PATCH] Update cheatsheet.en.md --- .../02.plane-refracting-surface-overview/cheatsheet.en.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/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 b/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 index 3fa90f525..16c720f00 100644 --- a/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 +++ b/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 @@ -105,8 +105,8 @@ defined, and therefore the spherical refracting surface becomes *quasi-stigmatic When spherical refracting surfaces are used under the following conditions, named **Gauss conditions** :
\- The *angles of incidence and refraction are small*
-(the rays are slightly inclined on the optical axis, and intercept the spherical surface in the vicinity of its vertex)
-Then *the spherical refracting surfaces* can be considered *quasi-stigmatic*, and therefore they can be used to build optical images. +(the rays are slightly inclined on the optical axis, and intercept the spherical surface in the vicinity of its vertex),
+then *the spherical refracting surfaces* can be considered *quasi-stigmatic*, and therefore they can be used to build optical images. Mathematically, when an angle $`\alpha`$ is small $`\alpha < or \approx 10 ^\circ`$, the following approximations can be made :
$`sin(\alpha) \approx tan (\alpha) \approx \alpha`$, and $`cos(\alpha) \approx 1`$.