list all the important, not-important derivations in ray optics...pls don't share links as I'm unable to open them 

Solution :

The list of derivations that are useful in the chapter, 'Ray optics' -
• Mirror formula 
• Rear depth and apparent depth
• Derivation of prism formula
• Power of lens formula
• Lens maker formula
• Angular dispersion 
• Total internal reflection - critical angle derivation
• Refraction at spherical surface
• Optical instruments derivation of formula for magnification