Question

Which of the following is the formula for this geometric sequence?

1, -3, 9, -27,...
A. an = -1(3)n-1
B. an = 1(-3)n-1
C. an = 3(-1)n-1

Answer 1

those n-1 are exponents

Answer 2

find the common ratio first\[r = \frac{a_n}{a_{n-1}}\]the formula for the n-th term is given by\[a_n = ar^{n-1}\]

Answer 3

thnk u @exraven