Question

Find a recursive rule for the nth term of the sequence.

5, 20, 80, 320, ...

Answer 1

`a_1 = 5`

`a_n = 4a_(n - 1)`

Explanation:

`a_1 = 5`

20/5 = 4

80/20 = 4

320/80 = 4

This a geometric sequence with r = 4.

`a_n = 4a_(n - 1)`

Answer:

`a_1 = 5`

`a_n = 4a_(n - 1)`