Question

What is the 8th term of the geometric sequence -1,3,-9....?

Answer 1

what is your ratio?

Answer 2

It doesn't say, would you like me to give you the choices?

Answer 3

-59,049
-6,561
2,187
19,683

Answer 4

no,no,you have to FIND it. the radio is found by dividing the second term by the first.

Answer 5

Oh, forgive me. I just started to learn this.

Answer 6

So it would be -3

Answer 7

\[a_n=a_1 \times r ^{n-1}\]
a(n)=the nth term
a(1)=the 1st term
r=common ratio

Answer 8

Ohhh okay. Let me explain what a geometric sequence is. a Geoemtric sequence .... ok Kaus hahaha

Answer 9

so we found our r=-3 and we're to find our 8th term. if we follow our formula \[\large a_{n}=a_{1}r^{n-1}\] we'll be looking for our 8th number, with this, we find it by, \[\large a_{8}=(-1)(-3)^{8-1}\]\[\large a_{8}=(-1)(-3)^{7}=2187\]

Answer 10

-6,561?

Answer 11

ARUGH

Answer 12

I need to study....

Answer 13

How did you get -6561? would you explain this to me? :P

Answer 14

But thank you so much!

Answer 15

Ill try another one on my own

Answer 16

Which calculus book are you using, by the way?Is it Stewart's?

Answer 17

I dont have a textbook, I work and take classes online.

Answer 18

Yeah, first find your ratio, your "a1" or first number, and then plug it into the equation to find the nth term, whatever you're looking for.

Answer 19

Ohh nevermind, I was going to direct you to the chapter for further study, haha.

Answer 20

SO this sequence is a1 = 1024 and a3=64
and I got 0.0625
Hoping thats correct?
@Jhannybean

Answer 21

which sequence? geometric? new problem?

Answer 22

New problem and yes geometric, but i already check and it was correct (:

Answer 23

Yay!! you're learning this stuff already!