MathDB
Like vasc's one or cmo i don't remember

Source: Tuymaada 2000

January 17, 2006
inequalitieslogarithmsinequalities proposed

Problem Statement

Prove for real x1x_1, x2x_2, ....., xnx_n, 0<xk120 < x_k \leq {1\over 2}, the inequality (nx1++xn1)n(1x11)(1xn1). \left( {n \over x_1 + \dots + x_n} - 1 \right)^n \leq \left( {1 \over x_1} - 1 \right) \dots \left( {1 \over x_n} - 1 \right).