IMO 2017 Shortlist G2
Let R and S be distin t points on ir le Ω, and let t denote the tangent line to Ω at R. Point R1 is the re e tion of R w...
Category: Geometry
Problem
Let R and S be distin t points on ir le Ω, and let t denote the tangent line to Ω at R. Point R1 is the re e tion of R with respe t to S. A point I is hosen on the smaller ar RS of Ω so that the ir um ir le Γ of triangle ISR1 interse ts t at two dierent points. Denote by A the ommon point of Γ and t that is losest to R. Line AI meets Ω again at J. Show that JR1 is tangent to Γ. (Luxembourg)