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Mathematics
Mathematics
Problem
For a sequence the sum of the first
n
n
n
terms is
S
n
=
n
(
2
n
+
3
)
S_n = n(2n + 3)
S
n
=
n
(
2
n
+
3
)
. Which pair correctly lists the general term
a
n
a_n
a
n
and the common difference
d
d
d
of this sequence? a)
a
n
=
2
n
+
3
,
d
=
2
a_n = 2n + 3,\; d = 2
a
n
=
2
n
+
3
,
d
=
2
b)
a
n
=
4
n
+
1
,
d
=
4
a_n = 4n + 1,\; d = 4
a
n
=
4
n
+
1
,
d
=
4
c)
a
n
=
4
n
−
1
,
d
=
4
a_n = 4n - 1,\; d = 4
a
n
=
4
n
−
1
,
d
=
4
d)
a
n
=
2
n
2
+
3
,
d
=
4
n
a_n = 2n^2 + 3,\; d = 4n
a
n
=
2
n
2
+
3
,
d
=
4
n
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