Question

Encontre a soma dos 8 primeiros termos da PG (3,21,...)

Answer 1

An=?
n=8
A1=3
q=7

an=A1.qⁿ-¹
an= 3 . 7^8-1
an=3 . 7^7
an=3 . 823543
an= 2470629

Answer 2

sn= a1.q^n-1/q-1
nesta pg
o
a1= 3
q=7
n=8

Sn =3.7^8-1/ 7-1
sn= 3.5764801 -1 / 7-1
Sn = 17294403 -1 / 6
Sn = 17294402/6
Sn = 17294402833