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All-Russian Olympiad
2014 All-Russian Olympiad
2
Prove that f(x) lies in [0,1]
Prove that f(x) lies in [0,1]
Source: All Russian 2014 Grade 10 Day 1 P2
May 3, 2014
function
algebra
Russia
Functional inequality
Problem Statement
Given a function
f
:
R
→
R
f\colon \mathbb{R}\rightarrow \mathbb{R}
f
:
R
→
R
with
f
(
x
)
2
≤
f
(
y
)
f(x)^2\le f(y)
f
(
x
)
2
≤
f
(
y
)
for all
x
,
y
∈
R
x,y\in\mathbb{R}
x
,
y
∈
R
,
x
>
y
x>y
x
>
y
, prove that
f
(
x
)
∈
[
0
,
1
]
f(x)\in [0,1]
f
(
x
)
∈
[
0
,
1
]
for all
x
∈
R
x\in \mathbb{R}
x
∈
R
.
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