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Mathematics
Mathematics
Problem
Evaluate
∑
n
=
1
∞
[
4
(
3
7
)
n
+
(
−
1
)
n
6
(
1
2
)
n
]
\displaystyle\sum_{n=1}^{\infty}\bigl[4\,(\tfrac{3}{7})^{n}+(-1)^{n}\,6\,(\tfrac{1}{2})^{n}\bigr]
n
=
1
∑
∞
[
4
(
7
3
)
n
+
(
−
1
)
n
6
(
2
1
)
n
]
.
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