Question 1202668
Which term of the series 2187,729,243....is 1/9

The formula

{{{a[n]=a1*(1/r)^(n-1)}}}

a1 =2187

r= 729/2187 = 1/3

1/9 = 2187*(1/3)^(n-1)

(1/3)^(n-1) = 1/9*2187=1/19683 = (1/3)^9
using exponent rules

 n=10