IMO Shortlist 1999 problem N2
Dodao/la:
arhiva2. travnja 2012. Prove that every positive rational number can be represented in the form
where a,b,c,d are positive integers.
%V0
Prove that every positive rational number can be represented in the form $\dfrac{a^{3}+b^{3}}{c^{3}+d^{3}}$ where a,b,c,d are positive integers.
Izvor: Međunarodna matematička olimpijada, shortlist 1999