Question

Which term of the sequence
Which term of the sequence 2,1,1/2,1/4.......is 1/128?
11
24​

Answer 1

1/128 is 9th term

This is a GP series

a = 2 ,r = 1/2

a.r^(n-1) = 1/128

2.1/2^(n-1) = 1/128

2^(-n-2) = 128 ^-1

2^(-n-2) = 2^-7

-n-2 = -7

n+2=7

n=7-2=5

=>> n=5