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Mathematics
Mathematics
Problem
If
S
n
S_n
S
n
denotes the sum of the first
n
n
n
terms of an arithmetic progression, express
S
n
−
S
n
−
1
S_n - S_{n-1}
S
n
−
S
n
−
1
in terms of
a
a
a
and
d
d
d
.
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