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Mathematics
Mathematics
Problem
Which of the following expresses the
n
n
n
th term
a
n
a_n
a
n
of an arithmetic progression whose first term is
a
a
a
and common difference is
d
d
d
? a)
a
n
=
a
−
(
n
−
1
)
d
a_n = a - (n - 1)d
a
n
=
a
−
(
n
−
1
)
d
b)
a
n
=
a
+
n
d
a_n = a + nd
a
n
=
a
+
n
d
c)
a
n
=
a
+
(
n
−
1
)
d
a_n = a + (n - 1)d
a
n
=
a
+
(
n
−
1
)
d
d)
a
n
=
n
2
[
2
a
+
(
n
−
1
)
d
]
a_n = \dfrac{n}{2}\bigl[2a + (n - 1)d\bigr]
a
n
=
2
n
[
2
a
+
(
n
−
1
)
d
]
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