Question

HELP!!

Enter a recursive rule for the geometric sequence. 5, −10, 20, −40, ...
a1=
an=

Answer 1

`a_(n)` = 5
`(-2)^(n-1)`

Explanation:

The recursive rule for a geometric sequence is

`a_(n)` = a
`(r)^(n-1)`

where a is the first term and r the common ration

Here

r = - 10 ÷ 5 = 20 ÷ - 10 = - 2 and a = 5, thus

`a_(n)` = 5
`(-2)^(n-1)`

Answer 2

Explanation: