Question

Which choice is the explicit formula for the following geometric sequence? 0.2, -0.06, 0.018, -0.0054, 0.00162

Answer 1

aₙ = 0.2(-0.3)⁽ⁿ⁻¹⁾

Explanation:

Answer 2

aₙ = 0.2(-0.3)⁽ⁿ⁻¹⁾

Explanation:

The geometric sequence with the first term a, a common ratio r has the nth term given as

Tₙ = arⁿ⁻¹

where Tₙ is the nth term

From the given sequence

a = 0.2

r = -0.06/0.2

= -0.3

Hence the nth term

= 0.2 * -0.3ⁿ⁻¹

The right option is E