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2012 Swedish Mathematical Competition
4
4
Part of
2012 Swedish Mathematical Competition
Problems
(1)
a=1 or -1<a<0 if a is real root of nx^n-x^{n-1}-x^{n-2}-\cdots-x-1=0
Source: 2012 Swedish Mathematical Competition p4
4/30/2021
Given that
a
a
a
is a real solution to the polynomial equation
n
x
n
−
x
n
−
1
−
x
n
−
2
−
⋯
−
x
−
1
=
0
nx^n-x^{n-1}-x^{n-2}-\cdots-x-1=0
n
x
n
−
x
n
−
1
−
x
n
−
2
−
⋯
−
x
−
1
=
0
where
n
n
n
is a positive integer, show that
a
=
1
a=1
a
=
1
or
−
1
<
a
<
0
-1<a<0
−
1
<
a
<
0
.
algebra
polynomial