Question

Calcule a soma dos oito primeiros termos da pg (2, 10, 50,...)

Answer 1

Q = a₂/a₁
Q = 10/2 → 5

$S_{n} = \frac{a_{1} . (q^n -1) }{q -1}$

s8 = 2 . (5⁸ -1)/5 -1
s8 =  390624/2
s8 = 195312