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OlympiadBench / 1845 / Determine the largest real number a such that for all n≥1 and for…

Problem

Answer published by the source. Consult the official source to check your work against its answer.

question

Determine the largest real number aa such that for all n1n \geqslant 1 and for all real numbers x0,x1,,xnx_{0}, x_{1}, \ldots, x_{n} satisfying 0=x0<x1<x2<<xn0=x_{0}<x_{1}<x_{2}<\cdots<x_{n}, we have $$ \frac{1}{x_{1}-x_{0}}+\frac{1}{x_{2}-x_{1}}+\cdots+\frac{1}{x_{n}-x_{n-1}} \geqslant a\left(\frac{2}{x_{1}}+\frac{3}{x_{2}}+\cdots+\frac{n+1}{x_{n}}\right) .\tag{1} $$
Plain-text mathematical notation (without MathML)
Determine the largest real number a such that for all n≥1 and for all real numbers x₀,x₁,…,x_(n) satisfying 0=x₀<x₁<x₂<⋯<x_(n), we have

$$
\frac{1}{x_{1}-x_{0}}+\frac{1}{x_{2}-x_{1}}+\cdots+\frac{1}{x_{n}-x_{n-1}} \geqslant a\left(\frac{2}{x_{1}}+\frac{3}{x_{2}}+\cdots+\frac{n+1}{x_{n}}\right) .\tag{1}
$$
Original LaTeX notation
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 $0=x_{0}<x_{1}<x_{2}<\cdots<x_{n}$, we have

$$
\frac{1}{x_{1}-x_{0}}+\frac{1}{x_{2}-x_{1}}+\cdots+\frac{1}{x_{n}-x_{n-1}} \geqslant a\left(\frac{2}{x_{1}}+\frac{3}{x_{2}}+\cdots+\frac{n+1}{x_{n}}\right) .\tag{1}
$$

answer type

Numerical

is multiple answer

false

language

English

question type

Open-ended

subject

Math

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Source and history

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