Question

(8CQ) Find the sum of the geometric series.
20-10+5-5/2+...

Answer 1

B edge

Explanation:

Answer 2

b.
`(40)/(3)`

Explanation:

The given geometric series is;

`20-10+5-(5)/(2)+...`

The first term of this series is

`a_1=20`

The common ratio is

`r=(-10)/(20)=-(1)/(2)`

The sum to infinity of this series is

`S_(\infty)=(a_1)/(1-r)`

Substitute the given values to obtain;

`S_(\infty)=(20)/(1--(1)/(2))`

This implies that;

`S_(\infty)=(20)/((3)/(2))`

`S_(\infty)=(40)/(3)`