1999 Paper 1 Q3

Year: 1999
Paper: 1
Question Number: 3

Course: LFM Stats And Pure
Section: Quadratics & Inequalities

Difficulty: 1500.0 Banger: 1500.0

Problem

The \(n\) positive numbers \(x_{1},x_{2},\dots,x_{n}\), where \(n\ge3\), satisfy $$ x_{1}=1+\frac{1}{x_{2}}\, ,\ \ \ x_{2}=1+\frac{1}{x_{3}}\, , \ \ \ \dots\; , \ \ \ x_{n-1}=1+\frac{1}{x_{n}}\, , $$ and also $$ \ x_{n}=1+\frac{1}{x_{1}}\, . $$ Show that
  1. \(x_{1},x_{2},\dots,x_{n}>1\),
  2. \({\displaystyle x_{1}-x_{2}=-\frac{x_{2}-x_{3}}{x_{2}x_{3}}}\),
  3. \(x_{1}=x_{2}=\cdots=x_{n}\).
Hence find the value of \(x_1\).

No solution available for this problem.

Rating Information

Difficulty Rating: 1500.0

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Banger Rating: 1500.0

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Problem source
The $n$ positive  numbers  $x_{1},x_{2},\dots,x_{n}$, where  $n\ge3$, satisfy
$$
x_{1}=1+\frac{1}{x_{2}}\, ,\ \ \ 
x_{2}=1+\frac{1}{x_{3}}\, , \ \ \
\dots\; ,
\ \ \ x_{n-1}=1+\frac{1}{x_{n}}\, ,
$$
and also
$$
\ x_{n}=1+\frac{1}{x_{1}}\, .
$$
Show that
\begin{questionparts}
\item  $x_{1},x_{2},\dots,x_{n}>1$,
\item ${\displaystyle x_{1}-x_{2}=-\frac{x_{2}-x_{3}}{x_{2}x_{3}}}$,
\item $x_{1}=x_{2}=\cdots=x_{n}$.
\end{questionparts}
Hence find the value of $x_1$.