Find the sum of the following geometric series:
(i) to 5 terms;
(ii) to terms

Solution:

(i) to 5 terms;
Given that

Using the formula,
The sum of GP for terms

(ii) to terms;
Let to terms
Multiply and divide by we obtain,
upto terms ..upto terms terms terms
Using the formula,
The sum of GP for terms
In the above sum we have two G.Ps, so,