Question

The sum of the first three terms of a GP is - and the sum to infinity of the GP is
If the GP has a positive common ratio r. Find r and the first term.​

Answer 1

Answer:

Let the G.P be, a,ar,ar

2

,ar

3

............∞ where ∣r∣<1

Using given condition,

1−r

a

=3..(1) and

1−r

2

a

2

=3..(2)

Using operation (2)/(1)

1+r

a

=1⇒

1+r

3(1−r)

=1⇒r=

2

1

⇒a=3(1−

2

1

)=

2

3