Question

Find an explicit formula for the geometric sequence 1/2, -4, 32, -256

Answer 1

Explanation:

Common ratio r = a₂/a₁ = -4/(½) = -8

nth term = a₁rⁿ⁻¹ = ½(-8)ⁿ⁻¹

This can be further simplified to (-1)ⁿ⁻¹2³ⁿ⁻⁴