Question

What is the fifth term of the geometric sequence?
a1=120, a2=36, a3=10.8, a6=0.2916

Answer 1

Hi @momobay212,
\(\Huge \mathcal{\text{Welcome To OpenStudy}\ddot\smile} \)

Do you know how to find the common ratio?

Answer 2

Thanks! And no I don't know how to do that, I basically just started doing geometric series.

Answer 3

ok cool,
then you might wanna have a look at this tutorial:
http://openstudy.com/study#/updates/503bb2a0e4b007f9003103b0

Answer 4

The common ratio is the ratio of
2nd term/ 1st term
= 3rd term/ 2nd term
= ...
and so on

Answer 5

here
common ratio = r= a2/a1 = ...

Answer 6

Ah ok, so I just divide the number that comes before the next?

Answer 7

the next term, divided by the current term,
yes

Answer 8

How do I find the fifth term? Because there is a gap between the 3rd and 6th terms.

Answer 9

so if we have the common ratio,
we can get any term.

multiple ways.

we'll discuss one way here:
r = a6/a5

we know a6,
we found r

Answer 10

0.3= 0.2916/a5

Answer 11

is that right?

Answer 12

r = a2/a1 = 36/120 = 0.3
correct.

r = a6/a5

a5 = a6/r = 0.2916/0.3 = ...

Answer 13

0.972

Answer 14

Thank you so much!! :)

Answer 15

correct!
and welcome ^_^