Question

What is the equation for a geometric sequence with a first term of 2 and a second term of −8?

Group of answer choices

an = 2(8)n − 1

an = 2(−8)n − 1

an = 2(4)n − 1

an = 2(−4)n − 1

Answer 1

Divide second term/first term to get the common ratio r

From there the formula is a(n) = a1 * r^(n-1)

Plug in your first term a1 and the common ratio r into the formula. Do not change anything else in the formula.