2019 Greece National Olympiad Q2
Source: 2019 Greece National Olympiad
March 11, 2019
geometry
Problem Statement
Let be a triangle with .Let be the center of it's circumcircle and be the center
of minor arc \overarc{AB}.Line intersects at and the circumcircle of intersects at
,().The circumcircle of intersects at ,(),prove that .