Question

MilkPoppers
3. a. What is the common ratio of the sequence 2, -6, 18, -54,....
b. What are the next three terms in the sequence?

Answer 1

-54/18 = ?

Answer 2

-3 , right?

Answer 3

Find the rate first,

-54 / 18 = ?

18 / -6 = ?

and so on,

Then plug in what you know into a formula or simply enter it into a calculator.
Which one do you want to go with?

Answer 4

The explicit formula is: f(n) = f(1) • r^n-1

Use alt 7 to use the " • " dot :P

Answer 5

Okay, I don't understand.. I'm lost.. lol.
Okay, so -54 / 18 = -3

Answer 6

Yes, that's your rate.

Answer 7

Ohh, okay. So how do I find out that the next three numbers?

Answer 8

f(n) = f(1) • r^n-1

find the 5th 6th and 7th term

I'll do the 5th for you,


f(5) = f(1) • -3^5-1
f(5) = 2 • -3^4
f(5) = 2 •81
f(5) = 162

Answer 9

Okay, let me see here. It might take a moment. lol

Answer 10

Geddit?

Answer 11

No?

Answer 12

f(5) = f(1) -3^6-1
f(5) = 2 -3^5
f(5) = 2 -243
f(5) = -486 ?

Answer 13

Not f(5).. it's f(6)

f(6) = -486

Yes.

Answer 14

Ohh, I got it now. Thank you so much. Algebra isn't my thing anymore. lol

Answer 15

:p np

Answer 16

F(7) = f(1) -3^7 – 1
f(7) = 2 -3^6
f(7) = 2 729
F(7) = 1458

Answer 17

Yup

Answer 18

Thank you, I get it now. :D

Answer 19

yw

Answer 20

Gl :***

Answer 21

In those kind of problems do you always do the minus 1 in the first part of the equation?

Answer 22

That's the explicit formula you can always do the recursive. f(n) = f(n – 1) • r

Answer 23

Ohh, okay. lol thanks.

Answer 24

k