Question

What is the recursive formula of the geometric sequence?

1, 5, 25, 125, 625, ...


A) a1 = 5; an = an – 1 ⋅ (1) for n ≥ 2

B) an = (1) ⋅ (5)^n – 1 for n ≥ 1

C) a1 = 1; an = an – 1 ⋅ (5) for n ≥ 2

D) an = (1) ⋅ (1∕5)^n – 1 for n ≥ 1

Answer 1

The correct answer is B.

For n ≥ 1:

`a_(n) = {5}^(n - 1)`