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OlympiadBench / 2212 / Given a positive integer n≥2, determine the largest positive integer N…

Problem

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

question

Given a positive integer n2n \geq 2, determine the largest positive integer NN for which there exist N+1N+1 real numbers a0,a1,,aNa_{0}, a_{1}, \ldots, a_{N} such that (1) a0+a1=1na_{0}+a_{1}=-\frac{1}{n}, and (2) (ak+ak1)(ak+ak+1)=ak1ak+1\left(a_{k}+a_{k-1}\right)\left(a_{k}+a_{k+1}\right)=a_{k-1}-a_{k+1} for 1kN11 \leq k \leq N-1.
Plain-text mathematical notation (without MathML)
Given a positive integer n≥2, determine the largest positive integer N for which there exist N+1 real numbers a₀,a₁,…,a_(N) such that

(1) a₀+a₁=−(1)/(n), and

(2) (a_(k)+a_(k−1))(a_(k)+a_(k+1))=a_(k−1)−a_(k+1) for 1≤k≤N−1.
Original LaTeX notation
Given a positive integer $n \geq 2$, determine the largest positive integer $N$ for which there exist $N+1$ real numbers $a_{0}, a_{1}, \ldots, a_{N}$ such that

(1) $a_{0}+a_{1}=-\frac{1}{n}$, and

(2) $\left(a_{k}+a_{k-1}\right)\left(a_{k}+a_{k+1}\right)=a_{k-1}-a_{k+1}$ for $1 \leq k \leq N-1$.

answer type

Expression

is multiple answer

false

language

English

question type

Open-ended

subject

Math

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Official source

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