Question

Calcule a soma dos 50 primeiros termos da sequencia (3,6,12...)

Answer 1

Vamos lá:
$S_{50} = \frac{(a_{1} .( q^{49} - 1))}{q - 1} \\ a_{1} = 3 \\ a_{2} = a_{1}. q^{1} \\ 6 = 3.q \\ q = 2 \\ S_{50} = \frac{(3 .( 2^{49} - 1))}{2 - 1} \\ S_{50} = 3.2^{49} - 3 \\ S_{50} =1688849860263933$