MathDB
Problems
Contests
National and Regional Contests
China Contests
XES Mathematics Olympiad
the 15th XMO
2
2
Part of
the 15th XMO
Problems
(1)
Inequality in XMO
Source: XMO 15th
4/30/2024
n
n
n
is a integer and
a
1
,
a
2
,
…
,
a
n
∈
[
−
1
,
1
]
a_1, a_2, \ldots, a_n\in[-1,1]
a
1
,
a
2
,
…
,
a
n
∈
[
−
1
,
1
]
are real numbers with
∑
i
=
1
n
a
i
=
0
\sum_{i=1}^{n}a_{i}=0
∑
i
=
1
n
a
i
=
0
,try to find the maximum value of
∑
1
≤
i
,
j
≤
n
,
i
≠
j
∣
a
i
−
a
j
2
∣
\sum_{1\leq i , j \leq n , i\ne j}|a_{i}-a^2_j|
1
≤
i
,
j
≤
n
,
i
=
j
∑
∣
a
i
−
a
j
2
∣
inequalities