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Check whether the following sequence is G.P. If so, write tn. 5,15,155,1255, ...

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प्रश्न

Check whether the following sequence is G.P. If so, write tn.

`sqrt(5), 1/sqrt(5), 1/(5sqrt(5)), 1/(25sqrt(5))`, ...

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उत्तर

`sqrt(5), 1/sqrt(5), 1/(5sqrt(5)), 1/(25sqrt(5))`, ...

t1 = `sqrt(5)`, t2 = `1/sqrt(5)`, t3 = `1/(5sqrt(5))`, t4 = `1/(25sqrt(5))`, ...

Here, `"t"_2/"t"_1 = "t"_3/"t"_2 = "t"_4/"t"_3 = 1/5`

∴ the ratio of any two consecutive terms is a constant, hence the given sequence is a Geometric progression.

Here, a = `sqrt(5)`, r = `1/5`,

tn = arn–1

∴ tn = `sqrt(5)(1/5)^("n" - 1)`

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पाठ 2: Sequences and Series - Exercise 2.1 [पृष्ठ २७]

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बालभारती Mathematics and Statistics (Arts and Science) Part 2 [English] Standard 11 Maharashtra State Board
पाठ 2 Sequences and Series
Exercise 2.1 | Q 1. (iii) | पृष्ठ २७

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