MathDB
Problems
Contests
National and Regional Contests
Iran Contests
Iran MO (2nd Round)
2016 Iran MO (2nd Round)
6
Function number theory
Function number theory
Source: Iran second round 2016,day2,problem6
April 29, 2016
function
number theory
Problem Statement
Find all functions
f
:
N
→
N
f: \mathbb N \to \mathbb N
f
:
N
→
N
Such that: 1.for all
x
,
y
∈
N
x,y\in N
x
,
y
∈
N
:
x
+
y
∣
f
(
x
)
+
f
(
y
)
x+y|f(x)+f(y)
x
+
y
∣
f
(
x
)
+
f
(
y
)
2.for all
x
≥
1395
x\geq 1395
x
≥
1395
:
x
3
≥
2
f
(
x
)
x^3\geq 2f(x)
x
3
≥
2
f
(
x
)
Back to Problems
View on AoPS