MathDB
Inequality on 1/(i^2 + i)^(3/4)

Source: Philippines MO 2016/3

January 21, 2017
inequalitiesalgebra

Problem Statement

Let nn be any positive integer. Prove that i=1n1(i2+i)3/4>22n+1\sum^n_{i=1} \frac{1}{(i^2+i)^{3/4}} > 2-\frac{2}{\sqrt{n+1}}.