Write the recursive formula for the geometric sequence.

a1 = -2 a2 = 8 a3 = -32

Question

Write the recursive formula for the geometric sequence.

 a1 = -2  a2 = 8  a3 = -32

shamil98 · Answer

a1 = -2 
a2 = 8
a3 = -32

think, what number is multiplied each time?

shamil98 · Answer

hint: try finding out the ratio of two consecutive terms, 
a2/a1 = ?

anonymous · Answer

-4?

shamil98 · Answer

yes.

anonymous · Answer

what does that even mean? ratio of a2/a1
 like I don't even .. idk dude

shamil98 · Answer

so -4 is multiplied each time to produce the next number in the sequence.

for a geometric sequence you need to find the ratio in order to find the recursive formula.

since the ratio is -4
your formula would be:
a_n = a_n-1 * -4

shamil98 · Answer

$$a_n = -4 a_{n-1}$$

shamil98 · Answer

the recursive formula for a geometric sequence is as such:
$$a_n = a_{n-1} * r $$
where r is your ratio

anonymous · Answer

ummmmm okay 
thank you for helping me even though I have no clue what just happened