MathDB
Geometry Problem

Source: 1989 National High School Mathematics League, Exam Two, Problem 1

February 25, 2020
geometry

Problem Statement

In ABC\triangle ABC, AB>ACAB>AC, bisector of outer angle A\angle A intersects circumcircle of ABC\triangle ABC at EE. Projection of EE on ABAB is FF. Prove that 2AF=ABAC2AF=AB-AC.