CBSE BOARD X, asked by dhillondhillon437, 10 months ago

find the sum of first 22 terms of the ap 8, 3, -2

Answers

Answered by brainlyaryan12
7

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→find the sum of first 22 terms of the ap 8, 3, -2

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⇒Given:

  • ⇒a = 8
  • ⇒d = 3-8 = -5
  • ⇒n = 22

⇒To Find:

  • S_{22}=?

Solution:- (Using Formula)

S_{22}=\frac{{\cancel{22}}^{\large{11}}}{{\cancel{2}}}\bigg(2\times 8+(22-1)\times -5\bigg)

S_{22}=11\bigg(16-105\bigg)

S_{22}=-89\times 11

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Formulas Used :-

  • S_n=\frac{n}{2}\big(2a+(n-1)d\big)

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Answered by lipikag979
1

since the first term and common difference can be found out

so we can find out the 22nd ten i.e. the last term(l)

and by using formula we can find the sum

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