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Byju's Answer
Standard XI
Mathematics
Sequence
Find the indi...
Question
Find the indicated terms in each of the following sequences whose
n
th terms are
a
n
=
3
n
−
2
4
n
+
5
;
a
7
and
a
8
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Solution
The
n
t
h
term of the sequence is
a
n
=
3
n
−
2
4
n
+
5
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
e
q
(
1
)
1) To find the seventh term of sequence
(
a
7
)
put n=7 in eq(1)
⟹
a
7
=
3
×
7
−
2
4
×
7
+
5
⟹
a
7
=
21
−
2
28
+
5
⟹
a
7
=
19
33
2)To find the eighth term of sequence
(
a
8
)
put n=8 in eq(1)
⟹
a
8
=
3
×
8
−
2
4
×
8
+
5
⟹
a
8
=
24
−
2
32
+
5
⟹
a
8
=
22
37
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Similar questions
Q.
Find the indicated terms in each of the following sequences whose
n
th terms are
a
n
=
n
(
n
−
1
)
(
n
−
2
)
;
a
5
and
a
8
Q.
Find the indicated terms in each of the sequences whose
n
t
h
terms are given by
(i)
a
n
=
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+
2
2
n
+
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;
a
7
,
a
9
(ii)
a
n
=
(
−
1
)
n
2
n
+
3
(
n
+
1
)
;
a
5
,
a
8
(iii)
a
n
=
2
n
2
−
3
n
+
1
;
a
5
,
a
7
(iv)
a
n
=
(
−
1
)
n
(
1
−
n
+
n
2
)
;
a
5
,
a
8
Q.
Find the indicated terms in each of the following sequences whose
n
th terms are
a
n
=
(
−
1
)
n
n
;
a
3
,
a
5
,
a
8
Q.
Find the indicated terms in each of the following sequences whose nth terms are:
(a) a
n
= 5n − 4; a
12
and a
15
(b)
a
n
=
3
n
-
2
4
n
+
5
;
a
7
a
n
d
a
8
(c) a
n
= n (n −1) (n − 2); a
5
and a
8
(d) a
n
= (n − 1) (2 − n) (3 + n); a
1
, a
2
, a
3
(e) a
n
= (−1)
n
n ; a
3
, a
5
, a
8