Let ABC be an acute-angled triangle with circumcircle ω and circumcentre O. Points D=B and E=C lie on ω such that BD⊥AC and CE⊥AB. Let CO meet AB at X, and BO meet AC at Y.Prove that the circumcircles of triangles BXD and CYE have an intersection lie on line AO.Ivan Chan Kai Chin, Malaysia geometryIMO ShortlistAZE IMO TST