Maximum of f_k(x,y) with x^2+y^2=1
Source: Austrian Federal Competition for Advanced Students 2011, #2
May 15, 2011
inequalitiesinequalities proposed
Problem Statement
For a positive integer and real numbers and , let
f_k(x,y)=(x+y)-\left(x^{2k+1}+y^{2k+1}\right)\mbox{.}
If , then determine the maximal possible value of .