MathDB
Putnam 1946 B2

Source: Putnam 1946

March 13, 2022
Putnamconicsparabola

Problem Statement

Let A,BA, B be two variable points on a parabola P0P_{0}, such that the tangents at AA and BB are perpendicular to each other. Show that the locus of the centroid of the triangle formed by A,BA,B and the vertex of P0P_0 is a parabola P1.P_1 . Apply the same process to P1P_1 and repeat the process, obtaining the sequence of parabolas P1,P2,,PnP_1, P_2 , \ldots, P_n. If the equation of P0P_0 is y=mx2y=m x^2, find the equation of Pn.P_n .