NCERT Class XI Mathematics - Sequences and Series - Solutions

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Question : 6
Total: 106
an = n
n2+5
4
Solution:  
We have, an = n
n2+5
4

Substituting n = 1, 2, 3, 4, 5, we get
a1 = 1.
12+5
4
=
6
4
=
3
2
, a2 = 2.
22+5
4
=
2.9
4
=
9
2

a3 = 3.
35+5
4
=
3.14
4
=
21
2
, a4 = 4.
42+5
4
=
4.21
4
= 21
a5 = 5.
55+5
4
=
5.30
4
=
75
2

∴ The first five terms are
3
2
,
9
2
,
21
2
,21
,
75
2

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