Coordinate axis and prime numbers
Source: IMO LongList 1988, Hong Kong 2, Problem 26 of ILL
October 22, 2005
analytic geometrynumber theoryprime numbersgreatest common divisorgeometry unsolvedgeometry
Problem Statement
The circle meets the coordinate axis at and Let and be two points on the circumference of the circle. Let be the point of intersection of and the -axis, and be the foot of the perpendicular drawn from to the -axis. If is odd, where and are prime numbers and and are natural numbers, show that