IMO 2009 Problem 5
- Day 2
- Answer
Determine all functions from the set of positive integers to the set of positive integers such that, for all positive integers and , there exists a non-degenerate triangle with sides of lengths (A triangle is non-degenerate if its vertices are not collinear.)
Proposed by Bruno Le Floch, France
Official text Transcription from AI-MO AoPS, checked word for word against the official paper. Quoted with source.
Official text: IMO 2009 official English paper, page 2.
Show the answer
f(n) = n for all positive integers n
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.