(From the 2001 Russian Math Olympiad, Grade 11)
Almost no "short answer" questions; everything requires a rigorous proof. russian math olympiad problems and solutions pdf verified
Verified problems and solutions for the All-Russian Mathematical Olympiad (RusMO) and former Soviet Union Math Competitions (From the 2001 Russian Math Olympiad, Grade 11)
But also ( P(x, f(y)) ): ( f(x f(f(y)) + f(x)) = f(y) f(x) + x ) ⇒ ( f(x y + f(x)) = f(x) f(y) + x ). (From the 2001 Russian Math Olympiad