Which term of the G.P. (i)

From the question it is given that,

Last term = 128

First term a = 2,

Then,

   

Then,

   

Now, comparing the powers

   

Therefore, 128 is the 13^th term.

(ii)

   

Solution:-

From the question it is given that,

Last term (a_n) = 1/243

First term a = 1,

Then

   

Then,

   

By comparing both left hand side and right hand side,

   

Therefore,

   

term.