Question

What is the 6th term of the geometric sequence shown?
80, 40, 20, . . .

Answer 1

Hello! Welcome to OpenStudy! Do you see a pattern happening here?

Answer 2

no

Answer 3

Well, what happens from 80 to 40?

Answer 4

it goes down 20

Answer 5

It is cut in half

Answer 6

yah

Answer 7

So what is half of 20? That will be the 4th number in the sequence

Answer 8

10

Answer 9

Good, now half of 10?

Answer 10

then 5

Answer 11

Yep, and lastly, half of 5 is?

Answer 12

2.5 or 2 1/2

Answer 13

Exactly!

Answer 14

thank you so much

Answer 15

No problem! :)

Answer 16

Do you need any more help?

Answer 17

the formula for geometric sequence is \[A(n)=a*r^{n-1}\], where n is term number, A(n) is the nth term, ,a is first term, and r is common ratio

Answer 18

no I should be good for know!

Answer 19

Okay, you can give a medal to whoever you think gave the best explanation by clicking the blue "Best Response" button :)

Answer 20

I did again thank you for the help :)

Answer 21

@Misam328 the method sleepyjess showed you is good. but if you have to find 50th term it will be hard to do this way. But you can use formula i gave for geometric sequence. For arithmetic it would look like
\[a(n)=a_1+(n-1)*d\] where d is common difference, n is the number of term you want to find, and a_1 is first term