Question

5, 10, 20, 40, ...

What is the common ratio, recursive formula, and explicit formula.
Is it geometric?

Answer 1

5 10 20 40

10/5 = 2

20/10 = 2

40/20 = 2

Common ratio:
`r=2`

Explicit formula:
`a_n = 5 (2^(n-1))`

Recursive:

`a_(n+1) = 2 a_n`

`a_1 = 5`

This is a geometric sequence.