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Mathematics — Analysis And Approaches
Mathematics — Analysis and Approaches
Problem
Explain in at most two sentences why
∑
k
=
0
n
(
−
1
)
k
(
n
k
)
=
0
\displaystyle\sum_{k=0}^{n}(-1)^k{n\choose k}=0
k
=
0
∑
n
(
−
1
)
k
(
k
n
)
=
0
for every positive integer
n
n
n
.
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