Question

Calcule a soma dos termos da Pa (131,138...565)

Answer 1

Boa noite!


An = a1+(n-1)·r
565 = 131+(n-1)·7
565 = 131+7n-7
565 - 7n = 131-7
-7n = 131-7-565
-7n = 124-565
-7n = -441 (-1)
7n = 441
n = 441/7
n = 63
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An ⇒ 565
N ⇒ 63
A1 ⇒ 131
R ⇒ a2-a1 ⇒ 138-131 = 7
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Sn = (a1+an)·n
              2

S63 = (131+565)·63
                   2

S63 = 696·63
               2


S63 =43848
              2

S63 =21924
 
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Att;Guilherme Lima