- #1

difalcojr

- 352

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- TL;DR Summary
- Is the paraxial equation for a spherical surface an exact equation or an approximate equation? It gives an exact answer, an exact, axial measurement, so it is exact. However, it is only derived using approximations for the very small, paraxial angles and axial distances, to my knowledge. Every text author has used a slightly different derivation with their own chosen, model variables. Does this matter in a logical, mathematical way? Is it a moot point, or just semantics, do you think?