Question

PLEASE HELP MEDAL WILL BE REWARDED!!!!!!
Write the sum using summation notation, assuming the suggested pattern continues.

2 - 6 + 18 - 54 + ...

Very Confused...

Answer 1

Look for a pattern...
2
-6
18
-54

This is a hunch... but don't you just keep multiplying a certain number to it? ;)

Answer 2

I think they are being multiplied by 3 :

So we can write them as :
\(x- 3x + 9x - 27x ...\)

Answer 3

@terenzreignz Yes! -3! so the answer has to be in summation notation form now where do i go ?

Answer 4

\[\sum_{i=1}^{?}-3(i-1)\]

Answer 5

it looks wrong though

Answer 6

@Chelsea04 So close but its not one of the answers! I will give you the 4 answers i can choose from

Answer 7

the format's probably not right but the idea is there,
if you times 2 but -3 you get -6
if you times -6 by -3 you get 18
if you times 18 by -3 you get -54

Answer 8

\[\sum_{n=0}^{\infty}2(-3)^n\]

Answer 9

\[\sum_{n=0}^{\infty}2(3)^n\]

Answer 10

the first one, i think

Answer 11

\[\sum_{n=0}^{?\infty}2(3)^(n+1)\]

Answer 12

\[\sum_{n=0}^{\infty}2(-3)^(n-1)\]

Answer 13

it seems like the first one you wrote

Answer 14

I think its the last one byt im not sure...

Answer 15

Ill go with the first one then!! You are probably right! :)

Answer 16

if you sub in 0 into the last one, the first value you get is 2/-3 or something like that