Question

Enter a recursive rule for the geometric sequence.

5, −10, 20, −40, ...

a1= an=

Answer 1

Answer:

$x_{n} = 5 \ * \ (-2)^{n-1}$

Step-by-step explanation:

Given the geometric sequence:

5, −10, 20, −40, ...

The first term is a = 5  

And the common ratio = r = -10/5 = -2

The general rule of geometric sequence is

$x_{n} = a \ * \ r^{n-1}$

So, the rule for the given geometric sequence is:

$x_{n} = 5 \ * \ (-2)^{n-1}$