Question

Is the sequence 5, 9, 15, ... an arithmetic sequence? Explain. Type your answer below.

Answer 1

What's difference between 5 and 9? Also, what's the difference between 9 and 15?

Answer 2

Well for the first it would be 4 and 6

Answer 3

An arithmetic sequence is a constant change between numbers, since 4 and 6 is not a constant change between them...

Answer 4

In order for sequence to be arithmetic sequence, the difference between all terms to their next term must be same.

ex: 2,4,6,8,10,12 ...

So that make this sequence not arithmetic sequence.

Answer 5

If it's not arithmetic would it be geometric then??

Answer 6

hmm, I would say not enough information were given, but what we know is that it's not arithmetic sequence.

Answer 7

Ok. I have a question.

Answer 8

What is the difference between geometric and arithmetic? I know if the numbers are constant that would be arithmetic. So what would be geometric?

Answer 9

Geometric is if each number gets multiplied by the same constant number. Such as:
3, 9, 27

They get multiplied by 3.

Answer 10

What?? I thought that it was arithmetic??

Answer 11

Think of arithmetic as "adding"
geometric is "multiplying"

Answer 12

No, Arithmetic is adding, Geometric is multiplying.

Answer 13

So confusing...

Answer 14

Arithmetic: 3, 6, 9, 12
Geometric: 3, 9, 27, 81

See the difference?

Answer 15

So geometric is only multiplying??? I don't get this.....

Answer 16

In arithmetic, you obtain next term by adding;
in geometric, you obtain next term by multiplying.

Answer 17

Basically so.

Answer 18

Ok. Now if it does NOT go by the same number lets say like from 3 to 9 to 28 to 30. What would that be?

Answer 19

What would that be called??

Answer 20

Hmm. I do not really think that would have much of a pattern. Is that a question you were given or just curious for general knowledge?

Answer 21

It's a question.

Answer 22

Do you have the full question by chance? Or is that it?

Answer 23

That came with the question...

Answer 24

That's it.

Answer 25

If you wouldn't mind pasting the whole question in? Just so I can take a look?

Answer 26

Ok. That question above and then it said: If it is not an arithmetic, what will the solution be called?

Answer 27

@jim_thompson5910 @whpalmer4 @mathmale @johnweldon1993 Do you know this question??

Answer 28

My apologies, I cannot seem to find a pattern in 3, 9, 28, 30.

Answer 29

I think she means this sequence 5, 9, 15, ...

Answer 30

It doesn't have to be in that order. I was just giving an example...Even that what geerky posted..

Answer 31

Somebody has to know this..........lol...

Answer 32

3, 9, 28, 30 is NOT arithmetic because the change from 3 to 9 is +6, but going from 9 to 28 is +19. This change should be constant. It should either be +6 all the time or +19 all the time.


It's also not geometric because 9/3 = 3

but 28/9 = 3.33333....

if 3, 9, 28, 30 was geometric, then dividing each term by its previous term would give you the same number. Another way to see it

3 ---> 9 (multiply by 3)
9 ---> 28 (multiply by 3.3333...)

the number you're multiplying by has changed. So that's why 3, 9, 28, 30 is not geometric

Answer 33

So...If it is NEITHER.....what is it called?? That is what I'm aiming at. That is what my question asks.

Answer 34

If it's neither, then it usually doesn't have a name. A lot of sequences out there are nameless.

Answer 35

So I'd just go with "neither"

Answer 36

hahahha!:) lol..your funny.

Answer 37

I believe jim_thompson5910 is right. I was stuck at thinking that, but then I thought, who would ask that kind of question.

Answer 38

Alright..Cuz my teachers said that there was a specific name for it.So i would just go with"neither" too... And yes!! he's very smart!!

Answer 39

Out of curious, what this sequence is called?
5, 9, 15, 23, 33, ...

I am sure this sequence has name, can someone ring a bell?