मराठी

The 4th term of a G.P. is 16, and the 7th term is 128. Its first term is ______. - Mathematics

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प्रश्न

The 4th term of a G.P. is 16, and the 7th term is 128. Its first term is ______.

पर्याय

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उत्तर

The 4th term of a G.P. is 16, and the 7th term is 128. Its first term is 2.

Explanation:

The 4th term of a G.P. = 16

`=> ar^(4-1) = 16`

7th term of G.P.  = 128

`=> ar^(7-1) = 128`

so, `(ar^3)/(ar^6) = 16/128`

`=> 1/r^3 = 1/8`

=> r = 2

`ar^3 = 16`

`a xx 2^3 = 16`

a x 8 = 16

a = 2

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पाठ 9: Arithmetic and geometric progression - Exercise 9F [पृष्ठ १९९]

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नूतन Mathematics [English] Class 10 ICSE
पाठ 9 Arithmetic and geometric progression
Exercise 9F | Q 10. | पृष्ठ १९९
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