How to easily prove focal length as half the radius of curvature for spherical mirrors?

Let us see how easy it is to prove that for spherical mirrors, the focal length is half the radius of curvature, i.e. f = R/2.

[@Parth_Wasnik]

Thank You Sir It Was Such A Nice Explanation

[@Rishabhkumar-bn2wd]

This is such a nice explanation , thank you

[@Anujkumar-ek3yi]

thanks sir your explanation is just awesome 🥰🥰🥰🥰👍

[@renujarnanayakkara7634]

❤❤

[@bhowal777]

Nice way to explain.

[@merrytitun]

👍👍

[@SSelpro-z5w]

Hi, sorry this does not work for spherical mirror. At 3:52 in your drawing CF=FX which is correct but CF+FX can not be equal to CX unless F is on the segment CX.