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Mathematics
Problem
What is the value of
∑
k
=
1
n
1
\displaystyle\sum_{k=1}^{n} 1\;
k
=
1
∑
n
1
for a positive integer
n
n
n
? a)
n
+
1
n+1
n
+
1
b)
n
(
n
+
1
)
2
\dfrac{n(n+1)}{2}
2
n
(
n
+
1
)
c)
n
n
n
d)
1
1
1
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