How Do Similar Triangles Derive the Thin Lens Equation?

AI Thread Summary
The discussion focuses on the derivation of the thin lens equation using similar triangles, specifically how congruent triangles contribute to the equation di/f - 1. It highlights that the derivation involves understanding refraction at spherical surfaces, applying Fermat's principle, and utilizing small angle approximations. The process is not straightforward and requires a solid grasp of optics principles. For a deeper understanding, resources like "Optics" by Hecht are recommended. The thin lens equations serve as approximations rather than exact representations of real-world scenarios.
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kk so i found out the steps involved deriving the thin lens equation, but what i don't get is when you have 2 similar triangles say triangle abd,edf are congruent how does the 2 triangles make it so its di/f-1. so what I am basically asking is can someone thourougly explain to me what's going on in the steps to deriving the thin lens equation thnx.
 
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Remember: the thin lens equations are only approximation to the real world. one way to get these formulas is to study refraction at spherical surfaces using Fermat's principle and small angle approximation, amongst other things. It is not a straight forward derviation. See for example: "Optics" by Hecht
 

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