Question

Calcule a soma dos 7 primeiros termos da P.G (1,3,9,27)

Answer 1

n=7
a1=1
q=3
an=a1*q^n-1
an=1*3^7-1
an=1*3^6
an=1*729
an=729

sn=an*q-a1/q-1
sn=729*3-1/3-1
sn=2187-1/2
sn=2186/2
sn=1093