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UPSC NDA 2 2012 Mathematics Paper
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© examsnet.com
Question : 99
Total: 120
What is the geometric mean of the sequence
1
,
2
,
4
,
8
,
2
n\/2
2
(
n
+
1
)
∕
2
2
(
n
+
1
)
−
1
2
(
n
−
1
)
Validate
Solution:
We know that geometric mean of
a
1
,
a
2
,
a
3
,
.
.
.
.
.
.
.
.
.
a
n
is
(
a
1
a
2
a
3
.
.
.
.
.
.
.
.
.
a
n
)
1
∕
n
=
2
n
(
n
+
1
)
2
⋅
1
n
=
2
n
+
1
2
.
© examsnet.com
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