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Putnam
2016 Putnam
B5
B5
Part of
2016 Putnam
Problems
(1)
Putnam 2016 B5
Source:
12/4/2016
Find all functions
f
f
f
from the interval
(
1
,
∞
)
(1,\infty)
(
1
,
∞
)
to
(
1
,
∞
)
(1,\infty)
(
1
,
∞
)
with the following property: if
x
,
y
∈
(
1
,
∞
)
x,y\in(1,\infty)
x
,
y
∈
(
1
,
∞
)
and
x
2
≤
y
≤
x
3
,
x^2\le y\le x^3,
x
2
≤
y
≤
x
3
,
then
(
f
(
x
)
)
2
≤
f
(
y
)
≤
(
f
(
x
)
)
3
.
(f(x))^2\le f(y) \le (f(x))^3.
(
f
(
x
)
)
2
≤
f
(
y
)
≤
(
f
(
x
)
)
3
.
Putnam
Putnam 2016
Putnam analysis
functional equation