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NDA · Maths · Sequence & Series
NDA Sequence & Series — Formulas 1
Question
1
of 13
1.
Which is the sum of the first n terms of a GP (r ≠ 1)?
A
S
n
=
a
(
r
n
−
1
−
1
)
r
−
1
S_n = \frac{a\,(r^{n-1} - 1)}{r - 1}
S
n
=
r
−
1
a
(
r
n
−
1
−
1
)
B
S
n
=
a
(
r
n
−
1
)
r
−
1
S_n = \frac{a\,(r^n - 1)}{r - 1}
S
n
=
r
−
1
a
(
r
n
−
1
)
C
S
n
=
a
(
1
−
r
n
)
r
+
1
S_n = \frac{a\,(1 - r^n)}{r + 1}
S
n
=
r
+
1
a
(
1
−
r
n
)
D
S
n
=
a
(
r
n
−
1
)
r
+
1
S_n = \frac{a\,(r^n - 1)}{r + 1}
S
n
=
r
+
1
a
(
r
n
−
1
)
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