Question

Which is the explicit formula for the sequence above?

Answer 1

aₙ=5*4ⁿ⁻¹

Explanation:

The common ratio is r=80/20=20/5=4

The explicit formula for a geometric sequence is aₙ=a₁*rⁿ⁻¹ where aₙ is the nth term, r is the common ratio, and a₁ is the first term.

Given:

a₁=5

r=4

Therefore, the explicit formula for the sequence is aₙ=5*4ⁿ⁻¹