MathDB
Romanian District Olympiad

Source: Grade XI

March 17, 2010
limitcalculuscalculus computations

Problem Statement

Prove that exists sequences (an)n0 (a_n)_{n\ge 0} with a_n\in \{\minus{}1,\plus{}1\}, for any nN n\in \mathbb{N}, such that: \lim_{n\rightarrow \infty}\left(\sqrt{n\plus{}a_1}\plus{}\sqrt{n\plus{}a_2}\plus{}...\plus{}\sqrt{n\plus{}a_n}\minus{}n\sqrt{n\plus{}a_0}\right)\equal{}\frac{1}{2}