Question

Cal. a soma dos 60 primeiros termos da P.A (5,10)

Answer 1

R = A2 - A1
R = 10 - 5
R = 5

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An = A1 + (n - 1)*r
An = 5 + ( 60 - 1)*5
An = 5 + 59*5
An = 5 + 295
An = 300

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Sn = (A1 + An)n/2
S60 = ( 5 + 300)60/2
S60 = 305 * 30
S60 = 9150


Resposta : S60 = 9150

Answer 2

a60 = 5 + 59 . 5
a60 = 300

s60 = (5 + 300) . 60/2
s60 = 305 . 30
s60 = 9150