MathDB
Problems
Contests
National and Regional Contests
Mathlinks Contests.
MathLinks Contest 5th
5.2
0552 algebra 5th edition Round 5 p2
0552 algebra 5th edition Round 5 p2
Source:
May 6, 2021
algebra
inequalities
function
5th edition
Problem Statement
Prove or disprove the existence of a function
f
:
S
→
R
f : S \to R
f
:
S
→
R
such that for all
x
≠
y
∈
S
x \ne y \in S
x
=
y
∈
S
we have
∣
f
(
x
)
−
f
(
y
)
∣
≥
1
x
2
+
y
2
|f(x) - f(y)| \ge \frac{1}{x^2 + y^2}
∣
f
(
x
)
−
f
(
y
)
∣
≥
x
2
+
y
2
1
, in each of the cases: a)
S
=
R
S = R
S
=
R
b)
S
=
Q
S = Q
S
=
Q
.
Back to Problems
View on AoPS