IMO Shortlist 2002 problem A1
Dodao/la:
arhiva2. travnja 2012. Find all functions
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from the reals to the reals such that
for all real
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.
%V0
Find all functions $f$ from the reals to the reals such that
$$f\left(f(x)+y\right)=2x+f\left(f(y)-x\right)$$
for all real $x,y$.
Izvor: Međunarodna matematička olimpijada, shortlist 2002