Question

What are the first three terms of a geometric sequence in which a5=25 and the common ratio is 5?

Answer 1

Answer:A

Explanation:

Answer 2

`(1)/(25)`,
`(1)/(5)`, 1

Explanation:

The n th term of a geometric sequence is

`a_(n)` = a₁
`(r)^(n-1)`

where a₁ is the first term and r the common ratio

Given

a₅ = 25 and r = 5, then

a₁
`(5)^(4)` = 25

625 a₁ = 25 ( divide both sides by 625 )

a₁ =
`(25)/(625)` =
`(1)/(25)`

a₂ = 5 × a₁ = 5 ×
`(1)/(25)` =
`(1)/(5)`

a₃ = 5 × a₂ = 5 ×
`(1)/(5)` = 1