Question

Complete the recursive formula of the geometric sequence -0.6, 3, -15, 75, ...

Answer 1

use this form 》Un = ar^(n - 1)

Answer 2

`\boxed{Un = 3(-5)^(n - 2)}`

Explanation:

We know that

a = -0,6 =
`-(3)/(5)` and r =
`(3)/(-0,6)` = -5

.

So

`Un = ar^(n - 1)`

`Un = (-(3)/(5) )(-5)^(n - 1)`

`Un = (3)(-5)^(-1)(-5)^(n - 1)`

`Un = 3(-5)^(n - 2)`