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MathNet 2016-part-02 — 184 problems (EN–VI) Question 46

Math Olympiad Vault · MathNet 2016-part-02 — 184 problems (EN–VI)

Question 46

Determine the largest real number $a$ such that for all $n \geqslant 1$ and for all real numbers $x_{0}, x_{1}, \ldots, x_{n}$ satisfying $0=x_{0} \lt x_{1} \lt x_{2} \lt \cdots \lt x_{n}$, we have
$$
\frac{1}{x_{1}-x_{0}}+\frac{1}{x_{2}-x_{1}}+\cdots+\frac{1}{x_{n}-x_{n-1}} \geqslant a\left(\frac{2}{x_{1}}+\frac{3}{x_{2}}+\cdots+\frac{n+1}{x_{n}}\right) \tag{1}
$$