Question

Write an expression for the general or nth term, an, for the geometric sequence. 1, -4, 16, -64, . . .

A. an = 1 • (-4)n-1

B. an = 1 • (-4)n

C. an = 1 • 4n-1

D. an = -1 • 4n

Answer 1

This is a geometric series, so each factor is a multiple of the previous. This multiple is -4.
\(a_1=(-4)^{0},a_2=(-4)^{1},...a_k=(-4)^{k}...\)

Answer 2

Hope this helps.