We can split the above expression into 2 parts. We will split 2n terms into 2 parts also which will leave it as n terms and another n terms .

=

Sum of a G.P. series is represented by the formula, , when |r|<1. ‘S_n’ represents the sum of the G.P. series upto n^th terms, ‘a’ represents the first term, ‘r’ represents the common ratio and ‘n’ represents the number of terms.

Here,

a =

r = (ratio between the n term and n-1 term)

n terms

∴

⇒

⇒

⇒

∴