NCERT Solutions class-11 Maths Exercise 9.1

Exercise 9.1

Write the first five terms of each of the sequences in Exercises 1 to 6 whose terms are:

1.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are 3, 8, 15, 24 and 35.

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2.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are and

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3.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are 2, 4, 8, 16 and 32.

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4.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are and

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5.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are and

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6.

Ans. Given:

Putting and 5, we get,

Therefore, the first five terms are and

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Find the indicated terms in each of the sequences in Exercises 7 to 10 where terms are:

7.

Ans. Given:

Therefore, 17^th and 24^th terms are 65 and 93 respectively.

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8.

Ans. Given:

Therefore, 7^th term is

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9.

Ans. Given:

Therefore, 9^th term is 729.

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10.

Ans. Given:

Therefore, 20^th term is .

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Write the first five terms of each of the sequences in Exercises 11 to 13 and obtain the corresponding series:

11. for all

Ans. Given: for all

Putting and 5, we get

Therefore, corresponding series is3 + 11 + 35 + 107 + 323 + ……….

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12.

Ans. Given:

Putting and 5, we get

Therefore, corresponding series is

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13.

Ans. Given:

Putting and 5, we get

Therefore, corresponding series is

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14. The Fibonacci sequence is defined by and Find for

Ans. Given: and

Putting 3, 4, 5 and 6, we have

Now,

For

For

For

For

For