Find the sum of the following series to infinity :

8 + + 4 + …. ∞

We observe that the above progression possess a common ratio. So it is a geometric progression.


Common ratio = r =


Sum of infinite GP = ,where a is the first term and r is the common ratio.


Note: We can only use the above formula if |r|<1


Clearly, a = 8 and r =


sum =


1