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International Contests
IMO Longlists
1984 IMO Longlists
49
Prove that x_i is either 0 or 1
Prove that x_i is either 0 or 1
Source:
October 12, 2010
algebra
polynomial
number theory unsolved
number theory
Problem Statement
Let
n
>
1
n > 1
n
>
1
and
x
i
∈
R
x_i \in \mathbb{R}
x
i
∈
R
for
i
=
1
,
⋯
,
n
i = 1,\cdots, n
i
=
1
,
⋯
,
n
. Set
S
k
=
x
1
k
+
x
2
k
+
⋯
+
x
n
k
S_k = x_1^k+ x^k_2+\cdots+ x^k_n
S
k
=
x
1
k
+
x
2
k
+
⋯
+
x
n
k
for
k
≥
1
k \ge 1
k
≥
1
. If
S
1
=
S
2
=
⋯
=
S
n
+
1
S_1 = S_2 =\cdots= S_{n+1}
S
1
=
S
2
=
⋯
=
S
n
+
1
, show that
x
i
∈
{
0
,
1
}
x_i \in \{0, 1\}
x
i
∈
{
0
,
1
}
for every
i
=
1
,
2
,
⋯
,
n
.
i = 1, 2,\cdots, n.
i
=
1
,
2
,
⋯
,
n
.
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