Pilot video lecture on Fermat's Principle
Additional Recourses:
I do not have recourses for learning more on this topic, as I have exceeded my own recourses in the lecture. The topic and example problems were inspired by Photonics 2nd ed. by Saleh and Teich and Differential Geometry and its Applications 2nd ed. by John Oprea.
Prerequisites:
The Calculus of Variations
Ordinary Differential Equations at the Single Variable Calculus Level
Literacy in Partial Derivatives