′ on the displacement of a ray through the Lagrangian image place within the paraxial focal aircraft, by differentiating the OPD expression given previously mentioned. The partial derivatives ∂OPD/∂ In 1841 Gauss published a now well-known treatise on optics where he shown that, as far as paraxial rays are concerned, https://trumanv947cks1.wikilinksnews.com/user