MathDB
17th ibmo - el salvador 2002./q5.

Source: Spanish Communities

April 14, 2006
inductionalgebra unsolvedalgebra

Problem Statement

The sequence of real numbers a1,a2,a_1,a_2,\dots is defined as follows: a1=56a_1=56 and an+1=an1ana_{n+1}=a_n-\frac{1}{a_n} for n1n\ge 1. Show that there is an integer 1k20021\leq{k}\leq2002 such that ak<0a_k<0.