Question

for the geometric sequence 1 2 4 find a8

Answer 1

Common ratio,\[r=2\]

First term,\[a_1=1\]

Good so far?

Answer 2

ogthot, please reply. Say something. Ask if you don't get something....

Answer 3

im still lost

Answer 4

SO you don't understand what I posted. Okay, so you don't understand anything, or just a part of my post?

Answer 5

i just need the answer

Answer 6

According to what I read from the Code of Conduct, this site prohibits straight forward answers.
I can tutor you, and help you understand better...

Answer 7

Getting straight answers won't get you anywhere. It will be quick, trust me. Just follow with me.

Answer 8

ok

Answer 9

Okay?

Answer 10

Sure...

Answer 11

So, do you understand what I mean when I say that r=2 (r is the common ratio) ?

Answer 12

yea

Answer 13

Yes, and we are also given that the first term, is 1.

Answer 14

There is a formula, for any geometric sequence.
\[a_n=a_1\times r^{n-1}\]

Answer 15

DO you see the formula?

Answer 16

i think would help a8=1(2)^8-1

Answer 17

no, it wouldn't. You are just spoon feeding, and I want the user to grasp the process and the understanding of how to do these problems. It would help to get the answer, but not the learning.... don't mean to be rude.

Answer 18

Okay, ogthot, again, there is a formula for geometric sequence..
\[a_n=a_1\times r^{n-1}\]
where a.n is the Nth term, and r to the power (n-1) is the number of "jumps" that you would need to get to the nth term.

Answer 19

Starting from the first term, you would have to multiply it times 3 to get the 4th term, and times 4 to get the 5th term, and times 5 to get the n6th term, and on... okay?

Answer 20

(by multiply it, I mean multiply the first term times the common ratio)