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National and Regional Contests
Iran Contests
Iran MO (2nd Round)
2009 Iran MO (2nd Round)
1
Polynomials - Iran NMO 2009 - Problem 1
Polynomials - Iran NMO 2009 - Problem 1
Source:
September 20, 2010
algebra
polynomial
quadratics
algebra proposed
Problem Statement
Let
p
(
x
)
p(x)
p
(
x
)
be a quadratic polynomial for which :
∣
p
(
x
)
∣
≤
1
∀
x
∈
{
−
1
,
0
,
1
}
|p(x)| \leq 1 \qquad \forall x \in \{-1,0,1\}
∣
p
(
x
)
∣
≤
1
∀
x
∈
{
−
1
,
0
,
1
}
Prove that:
∣
p
(
x
)
∣
≤
5
4
∀
x
∈
[
−
1
,
1
]
\ |p(x)|\leq\frac{5}{4} \qquad \forall x \in [-1,1]
∣
p
(
x
)
∣
≤
4
5
∀
x
∈
[
−
1
,
1
]
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