Question

a soma dos 12 primeiros termos da pg(8,40,...)

Answer 1

a1 = 8

q = 40 ÷ 8 = 5

S12 = ?

$S_{12}=\frac{8~*(5^{12}-1)}{5-1} \\ \\ S_{12}=\frac{8~*(244140625 ~-~1)}{4} \\ \\ S_{12}=2~*244140624\\ \\ S_{12}=488.281.248$