geometric sequence

Question

find the ninth term of the geometric sequence, given the first term and common ratio

a₁= 1

r= -1/3

Answer 1

The formula for the nth term of a geometric series is

a_n=a₁(r)^n-1

Plugging in the values

a₉=1(-1/3)^9-1

a₉=(-1/3)⁸

a₉=1/6561