Question

calcule o numero de termos da p.g (3,6,...,1536)

Answer 1

an=1536
a1=3
q=2
n=?

1536=3.2^n-1  
1536/3=2^n-1
512=2^n-1
2^9=2^n-1
9=n-1
N=9+1
n=10 

São 10 termos