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1982 IMO Shortlist
15
Prove the inequality for all s
Prove the inequality for all s
Source: IMO LongList 1982 - P19
September 10, 2010
Inequality
calculus
geometric progression
IMO Shortlist
IMO Longlist
Problem Statement
Show that
1
−
s
a
1
−
s
≤
(
1
+
s
)
a
−
1
\frac{1 - s^a}{1 - s} \leq (1 + s)^{a-1}
1
−
s
1
−
s
a
≤
(
1
+
s
)
a
−
1
holds for every
1
≠
s
>
0
1 \neq s > 0
1
=
s
>
0
real and
0
<
a
≤
1
0 < a \leq 1
0
<
a
≤
1
rational.
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