. * fovea Zeon 3) from Fermat's Principle it ! least time. SF = minimal ' : . . Derivation ‘ . of | . ; . 6) egvarions ah aR 5 , and [Zecause Frem h Vi, ; Cv, (Ye, 0) — e } inversion Ve of trajectory V Ve dA diag ram , to tymmerry: s) th, Vy): GA t an for > 7): '"~ = JS cote go : a Comeé. Cs ho, = Vive; Vo Ch 4+Vo for Ach, yeu } c,= ee and View VF — hk +Vo A cos9 frem 4) Vv, -V mo dh oF - Asin ede ha . dh= ~vi-ve and RA - i 4) For 3 ° small and | ' Case hs and { 3 bh A Weve = Ts Fyrom ! = A sinedé sin 6 R= BEST _%o A = - dé tas So hi Vo Go, R = VirVa . Si*® Se COS @s tan do % Go thie Go Vir Ve 4 AiVo ¥, “Vo tan Ge 6 @) LLNL c) 143