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Mathematics
Mathematics
Problem
Consider the infinite series
S
=
∑
n
=
1
∞
n
2
2
n
S=\displaystyle \sum_{n=1}^{\infty} \dfrac{n^{2}}{2^{\,n}}
S
=
n
=
1
∑
∞
2
n
n
2
. What is the value of
S
S
S
? a)
4
4
4
b)
12
12
12
c)
6
6
6
d)
3
3
3
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