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National and Regional Contests
Singapore Contests
Singapore Senior Math Olympiad
2013 Singapore Senior Math Olympiad
5
5
Part of
2013 Singapore Senior Math Olympiad
Problems
(1)
SMO Senior Round 2 Qn 5 2013
Source:
6/29/2013
Let
x
,
y
x,y
x
,
y
be distinct real numbers such that
x
n
−
y
n
x
−
y
\frac{x^n-y^n}{x-y}
x
−
y
x
n
−
y
n
is an integer for
4
4
4
consecutive positive integer
n
n
n
. Prove that
x
n
−
y
n
x
−
y
\frac{x^n-y^n}{x-y}
x
−
y
x
n
−
y
n
is an integer for all positive integers
n
n
n
.