The Student Room Group

Are patterned sequences always arithmetic?

Howdy :smile:.
Can patterned sequences be geometric? I can only seem to find arithmetic ones when looking at past exam questions.

I've attached a copy of what I'm looking at.

Screen Shot 2016-04-05 at 19.35.02.png

Thanks.
Reply 1
Original post by jojo55
Howdy :smile:.
Can patterned sequences be geometric?


Yes they can. Imagine a question that is broadly as follows: you are given (and drawn) a chocolate bar. You have n friends, each friend eats half of whatever the current chocolate size is. This forms a geometric series, find the size at person n (sequence) how much of the chocolate has been eaten at person 5 (sum), etc...
Reply 2
Original post by Zacken
Yes they can. Imagine a question that is broadly as follows: you are given (and drawn) a chocolate bar. You have n friends, each friend eats half of whatever the current chocolate size is. This forms a geometric series, find the size at person n (sequence) how much of the chocolate has been eaten at person 5 (sum), etc...


Ah, thanks for clearing that up :smile:.
Reply 3
Original post by jojo55
Ah, thanks for clearing that up :smile:.


Make sure you know both when you're going into the exam! :biggrin:
Original post by Zacken
Make sure you know both when you're going into the exam! :biggrin:


isn't this C1 and C2 stuff? or is this just a basic GCSE understanding of what they are????
Reply 5
Original post by thefatone
isn't this C1 and C2 stuff? or is this just a basic GCSE understanding of what they are????


C2 and C2 stuff is a basic GCSE understanding of what they are though. I don't see the difference?
Original post by Zacken
C2 and C2 stuff is a basic GCSE understanding of what they are though. I don't see the difference?


oh right in GCSE i just added numbers and multiplied xD

in C2 we learn some formulas for sequences and nth term formulas too?
Reply 7
Original post by thefatone
oh right in GCSE i just added numbers and multiplied xD

in C2 we learn some formulas for sequences and nth term formulas too?


All of which can be derived by adding number and multiplying, no? :tongue:
Original post by Zacken
All of which can be derived by adding number and multiplying, no? :tongue:


hmmm adding deciding rearranging, yea pretty much probably 1 or 2 new things like recurrence relations(why + how do i even remember this)
Reply 9
Original post by thefatone
hmmm adding deciding rearranging, yea pretty much probably 1 or 2 new things like recurrence relations(why + how do i even remember this)


Yeah, fair enough. I remember when I was preparing for C1/2, I didn't really bother learning arithmetic and geometric sequences and series beyond proving their formulas in the booklet. :lol:
Original post by Zacken
Yeah, fair enough. I remember when I was preparing for C1/2, I didn't really bother learning arithmetic and geometric sequences and series beyond proving their formulas in the booklet. :lol:


oh yea that's annoying, you do have to prove them >.>
Reply 11
Original post by thefatone
oh yea that's annoying, you do have to prove them >.>


It's not annoying. If you understand something, you should be able to prove it.
Original post by Zacken
It's not annoying. If you understand something, you should be able to prove it.


i remember i dropped 4 marks bc i forgot how to prove this stuff *cries

but now i know :colonhash: i will never ever forget that until after my c1 and c2 exams
Reply 13
Original post by thefatone
i remember i dropped 4 marks bc i forgot how to prove this stuff *cries

but now i know :colonhash: i will never ever forget that until after my c1 and c2 exams


You don't "forget'" or "remember" proofs, though. I certainly don't remember much, if any, proofs off the top of my head but I can usually run with the idea and come up with it on the spot.
Original post by Zacken
You don't "forget'" or "remember" proofs, though. I certainly don't remember much, if any, proofs off the top of my head but I can usually run with the idea and come up with it on the spot.


with me if you can forget it you will but you will also remember the most useless things you probably never needed to know again till you're in uni
Reply 15
Original post by thefatone
with me if you can forget it you will but you will also remember the most useless things you probably never needed to know again till you're in uni


Fair enough. :rofl:
Original post by Zacken
Fair enough. :rofl:


it really sucks having memory like mine, >.> all these common philosophers my mind just decides nope you won't remember what they did but that one philosopher who refuted 1 thing against this theory? yup you can remember what he said and what examples he used >.> :colonhash: it sucks so much, i put plenty of work in though..
Reply 17
Original post by thefatone
it really sucks having memory like mine, >.> all these common philosophers my mind just decides nope you won't remember what they did but that one philosopher who refuted 1 thing against this theory? yup you can remember what he said and what examples he used >.> :colonhash: it sucks so much, i put plenty of work in though..


FWIW, I have a crappy memory too - you don't really need a good one for maths. :-)
Original post by Zacken
FWIW, I have a crappy memory too - you don't really need a good one for maths. :-)


I think for everything, whether Economics, Physics, Chemistry or Mathematics - understanding is vital. Being able to make-out and derive the meaning behind something is much more rewarding than just remembering it.

We have a whole lot of readers nowadays, but too few people understand.
Reply 19
Original post by High Stakes
I think for everything, whether Economics, Physics, Chemistry or Mathematics - understanding is vital. Being able to make-out and derive the meaning behind something is much more rewarding than just remembering it.

We have a whole lot of readers nowadays, but too few people understand.


I agree enormously.

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