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1980 Poland - Second Round
2
2
Part of
1980 Poland - Second Round
Problems
(1)
x_1x_2x_3...x_n <= x_1^2 /2+ x_2^4 / 4 + x_3^8 /8 + ...+1/2^n
Source: Polish MO Recond Round 1980 p2
9/9/2024
Prove that for any real numbers
x
1
,
x
2
,
x
3
,
…
,
x
n
x_1, x_2, x_3, \ldots, x_n
x
1
,
x
2
,
x
3
,
…
,
x
n
the inequality is true
x
1
x
2
x
3
…
x
n
≤
x
1
2
2
+
x
2
4
4
+
x
3
8
8
+
…
+
x
n
2
n
2
n
+
1
2
n
x_1x_2x_3\ldots x_n \leq \frac{x_1^2}{2} + \frac{x_2^4}{4} + \frac{x_3^8}{8} + \ldots + \frac{x_n^{2^ n}}{2^n} + \frac{1}{2^n}
x
1
x
2
x
3
…
x
n
≤
2
x
1
2
+
4
x
2
4
+
8
x
3
8
+
…
+
2
n
x
n
2
n
+
2
n
1
algebra
inequalities