MathDB
I.S.I. B.Math.(Hons.) Admission test : 2010 Problem 2

Source:

April 12, 2012
functiongeometryintegrationcalculuscalculus computations

Problem Statement

In the accompanying figure , y=f(x)y=f(x) is the graph of a one-to-one continuous function ff . At each point PP on the graph of y=2x2y=2x^2 , assume that the areas OAPOAP and OBPOBP are equal . Here PA,PBPA,PB are the horizontal and vertical segments . Determine the function ff.
[asy] Label f; xaxis(0,60,blue); yaxis(0,60,blue); real f(real x) { return (x^2)/60; } draw(graph(f,0,53),red); label("y=x2y=x^2",(30,15),E); real f(real x) { return (x^2)/25; } draw(graph(f,0,38),red); label("y=2x2y=2x^2",(37,37^2/25),E); real f(real x) { return (x^2)/10; } draw(graph(f,0,25),red); label("y=f(x)y=f(x)",(24,576/10),W); label("O(0,0)O(0,0)",(0,0),S); dot((20,400/25)); dot((20,400/60)); label("PP",(20,400/25),E); label("BB",(20,400/60),SE); dot(((4000/25)^(0.5),400/25)); label("AA",((4000/25)^(0.5),400/25),W); draw((20,400/25)..((4000/25)^(0.5),400/25)); draw((20,400/25)..(20,400/60)); [/asy]