MathDB
Locus on a Circle

Source: OME 2014 3

July 16, 2014
geometrycircumcircleparallelogramconicsellipseperpendicular bisectorgeometry unsolved

Problem Statement

Let BB and CC be two fixed points on a circle centered at OO that are not diametrically opposed. Let AA be a variable point on the circle distinct from BB and CC and not belonging to the perpendicular bisector of BCBC. Let HH be the orthocenter of ABC\triangle ABC, and MM and NN be the midpoints of the segments BCBC and AHAH, respectively. The line AMAM intersects the circle again at DD, and finally, NMNM and ODOD intersect at PP. Determine the locus of points PP as AA moves around the circle.