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Mathematics
Mathematics
Problem
Determine
3
∑
k
=
1
n
k
+
2
∑
k
=
1
2
n
5
k
−
1
3\displaystyle\sum_{k=1}^{n}k\; +\; 2\displaystyle\sum_{k=1}^{2n}5^{k-1}
3
k
=
1
∑
n
k
+
2
k
=
1
∑
2
n
5
k
−
1
and simplify your answer fully.
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