Question

calcule a soma dos primeiros seis termos da p.g. (3,12,48...)

Answer 1

q=12/3 → q=4
$S_{6}$=a1(q^6-1)/q-1
$S_{6}$=3(4^6-1)/6-1
$S_{6}$=3(4096-1)/5
$S_{6}$=3(4095)/5
$S_{6}$=12285/5
$S_{6}$=2457