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National and Regional Contests
Kosovo Contests
Kosovo Team Selection Test
2019 Kosovo Team Selection Test
2
Kosovo TST 2019 P2
Kosovo TST 2019 P2
Source:
April 15, 2019
functional equation
algebra
function
Problem Statement
Determine all functions
f
:
R
→
R
f:\mathbb{R} \rightarrow \mathbb{R}
f
:
R
→
R
such that for every
x
,
y
∈
R
x,y \in \mathbb{R}
x
,
y
∈
R
f
(
x
4
−
y
4
)
+
4
f
(
x
y
)
2
=
f
(
x
4
+
y
4
)
f(x^{4}-y^{4})+4f(xy)^{2}=f(x^{4}+y^{4})
f
(
x
4
−
y
4
)
+
4
f
(
x
y
)
2
=
f
(
x
4
+
y
4
)
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