Question

Quantos termos a PG (36, 18, 9, ..., 9/16) tem? Apresente cálculo.

Answer 1

a1=36

an=9/16

an=a1.q^n-1

9/16=36.(1/2)^n-1

9/16/36=(1/2)^n-1
9/16.1/36=(1/2)^n-1

9/576=(1/2)^n-1

1/64=(1/2)^n-1

(1/2)^6=(1/2)^n-1
6=n-1
n=6+1
n=7