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Answered

what is the sum of the first fifteen terms for the sequence 3,5,7,9...?​

Sagot :

Sufarts123456789go

Answer:

255 ?

Step-by-step explanation:

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AGboiigo

Answer:

The sum is 255

Step-by-step explanation:

Formula of Sum in arithmetic sequence

  • Sn = n/2 (2a1+(n-1)d)

From the series

  • n = 15 , a1 = 3 and d = 2

d = 5-3 = 2

d = 7-5 = 2

Now , solving we get

  • Sn = n/2 (2a1 + (n-1)d)
  • S(50) = 15/2 [ 2(3) + (15-1)2 ]
  • S(50) = 7.5 [ 6 + 14(2) ]
  • S(50) = 7.5 ( 6 + 28)
  • S(50) = 7.5 (34)
  • S(50) = 255

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