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China Team Selection Test
2023 China Team Selection Test
P21
Inequality Problem
Inequality Problem
Source: 2023 China TST Problem 21
April 1, 2023
inequalities
Problem Statement
Given integer
n
≥
2
n\geq 2
n
≥
2
. Find the minimum value of
λ
\lambda {}
λ
, satisfy that for any real numbers
a
1
a_1
a
1
,
a
2
a_2
a
2
,
⋯
\cdots
⋯
,
a
n
{a_n}
a
n
and
b
{b}
b
,
λ
∑
i
=
1
n
∣
a
i
−
b
∣
+
n
∣
∑
i
=
1
n
a
i
∣
⩾
∑
i
=
1
n
∣
a
i
∣
.
\lambda\sum\limits_{i=1}^n\sqrt{|a_i-b|}+\sqrt{n\left|\sum\limits_{i=1}^na_i\right|}\geqslant\sum\limits_{i=1}^n\sqrt{|a_i|}.
λ
i
=
1
∑
n
∣
a
i
−
b
∣
+
n
i
=
1
∑
n
a
i
⩾
i
=
1
∑
n
∣
a
i
∣
.
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