Problem 2, Olympic Revenge 2010
Source: IX Olympic Revenge - 2010
January 28, 2013
geometryreal analysisreal analysis unsolved
Problem Statement
Joaquim, José and João participate of the worship of triangle . It is well known that is a random triangle, nothing special. According to the dogmas of the worship, when they form a triangle which is similar to , they will get immortal. Nevertheless, there is a condition: each person must represent a vertice of the triangle. In this case, Joaquim will represent vertice , José vertice and João will represent vertice . Thus, they must form a triangle which is similar to , in this order. Suppose all three points are in the Euclidean Plane. Once they are very excited to become immortal, they act in the following way: in each instant , Joaquim, for example, will move with constant velocity to the point in the same semi-plan determined by the line which connects the other two points, and which would create a triangle similar to in the desired order. The other participants act in the same way.
If the velocity of all of them is same, and if they initially have a finite, but sufficiently large life, determine if they can get immortal.Observation: Initially, Joaquim, José and João do not represent three collinear points in the plane