Question

The formula for any geometric sequence is an = a1 · rn - 1, where an represents the value of the nth term, a1 represents the value of the first term, r represents the common ratio, and n represents the term number. What is the formula for the sequence -3, -6, -12, -24, ...?

A an = -3 · 2 n - 1
B an = -3 · (-2) n - 1
C an = 2 · (-3) n - 1
D an = -2 · (-3) n - 1

Answer 1

an=-3.2n-1

Explanation:

a1=-3

r=T2/T1

-6/-3

r=2

an=-3.2n-1