MathDB
Strange Inequality

Source: ILL 1970 - Problem 19.

May 24, 2011
inequalitiesinequalities unsolved

Problem Statement

Let 1<nN1<n\in\mathbb{N} and 1aR1\le a\in\mathbb{R} and there are nn number of xi,iN,1inx_i, i\in\mathbb{N}, 1\le i\le n such that x1=1x_1=1 and xixi1=a+αi\frac{x_{i}}{x_{i-1}}=a+\alpha _ i for 2in2\le i\le n, where αi1i(i+1)\alpha _i\le \frac{1}{i(i+1)}. Prove that xnn1<a+1n1\sqrt[n-1]{x_n}< a+\frac{1}{n-1}.