depressed about c1/m1 maths papers...

mathlover002 · 2011-05-19 22:30:03

hi,

i am a year 11, and i just sat the core 1 and mechanics 1 papers on wednesday 18th may 2011, and i found core 1 quite hard. i really wanted to get 100 UMS in it because i did so much preparation, but looking at the mark scheme online i think i got 71 or 72 out of 75...which wouldnt be 100 UMS, would it? hopefully its still 90...i have aspirations of studying maths at oxbridge or a top university so if i couldn't even do some of the questions in this paper than i probably am not good enough for oxbridge, surely...

m1, i found really easy, but because of my stupidity i not only got the components of i and j the wrong way round, but then i thought that, to find the position vector of a boat (relative to origin) when it is northwest, you let the component of i be equal to the component of j and solve for t. which was apparently wrong, and i think i know why - because its northwest, the component of i is reversed to it is multipled by -1, right?

i feel like a complete idiot, getting a question like that wrong. i hope i didnt make any stupid mistakes in this paper that i didnt spot (yet), otherwise maybe i will get less than 70...maybe worse.

why did they have to make c1 so hard this year? i have the paper if anyone wants to see it (it should be ok since edexcel rules say you cant discuss it UNLESS 24 hours have passed)...does anyone want to go through the paper with me and help me understand a couple things?

like, there was a question saying:

consider a sequence: k + 2k + 3k + ... + 100

where k is a factor of 100. find

(a) an expression, in terms of k, for the number of terms in the sequence
(b) an expression, in terms of k, for the sum of terms in the sequence (or something like that)

both were worth 2 marks i think, i got both correct but i didnt understand the proper method to get the answer for (a). i got 100/k, but why is it that? i found that by just testing all the values of k (which should be technically correct because its an exhaustive proof of all cases, right?)...but some guy posted his method saying that:

nk = 100

therefore n = 100/k

no idea where he got nk from. i know that nk = 100 is true, but i dont know what he did to get there.

thanks for your help.

gAr · 2011-05-19 23:09:22

Hi mathlover002,

Don't worry, interest and curiosity is all you need to succeed.

If k is a factor of 100, then there would naturally be 100/k terms which are multiples of k.

Consider any of the factors:
[1, 2, 4, 5, 10, 20, 25, 50, 100]
If you take k=25, there would be 100/25 = 4 terms in the sequence.

Sum is of n terms is:

Bob · 2011-05-19 23:10:18

hi mathlover002

Welcome to the forum. There's lots in that post so apologies if I don't cover everything.

First of all, why not sign up to the forum. It's free and you'll find loads of folk who also love maths. But you're very welcome as a guest anyway.

If the paper was hard for everyone, then they'll adjust for that when they convert to UMS; that's what it's for.

Secondly, I'm guessing this was your first advanced level exam so it's not surprising you made a few silly mistakes; that can happen to anyone (all the time for me if you look at my past posts). Most students take this exam at 17, so you're a year early. Well done for getting to the standard. And you can resit! And bear in mind that Andrew Wiles made a mistake, after seven years work proving Fermat's Last Theorem; so if it can happen to him .......

Now to those k's.

If k is a factor of 100, then there must be an integer n so that nk = 100

The first term is k, the next 2k, the next 3k,.... the last nk, so n is a counter for how many terms there are.

But n = 100/k, so there are 100/k terms.

What sort of sequence is it?

It's an arithmetic progression with common difference k, first term k, and 100/k terms.

Plug into the formula for the sum of an AP

sum = N/2(2a + (N-1)d) = 100/2k(2k + (100/k -1)k) = 50(2 + (100/k -1)) = 50(1 + 100/k)

Oh hi there gAr. Nice to hear from you. I think this correction to mine makes it the same as yours.

Two further comments to mathlover002

After I posted this I looked it over and corrected three errors ( two spellings and one arithmetic). Learn from this .... check your exam answers carefully.

Secondly, if that's a C1 question then, yes, they have been a bit nasty with their questions. It's not 'off the syllabus', but it's got a twist to it that could easily put off many candidates.

And thirdly, (whoops see I cannot even count my comments) let's see some more of this paper please ... what board is it from?

Bob

Last edited by Bob (2011-05-19 23:41:47)

gAr · 2011-05-19 23:21:07

Hi Bob,

Nice to hear from you too.
How are you?

Bob · 2011-05-19 23:25:22

hi gAr,

I'm very well thanks, and you?

I think mathslover002 is in the UK; certainly a UK exam because of all the goobledegook about C1 M1 and UMS. And year 11 makes him/her 16; doing a course for 17 year olds. So that's impressive for a start!

I await further posts with interest.

Just re-read the OP Edexcel is the board. Yes, I'd like to help with other questions and finally

i have aspirations of studying maths at oxbridge or a top university

Is that an exclusive or. I suspect some oxbridge undergrads might have something to say about that

Bob

Last edited by Bob (2011-05-19 23:29:42)

gAr · 2011-05-19 23:50:24

Hi Bob,

I'm fine too.

Yes, even I have seen students around me. They work really hard, sometimes even skipping food and sleep, to get into "top" colleges/universities.

What concerns me is that many people who do get into such technical institutions, later go for management courses. Is it not a wastage of technical education?

...does anyone want to go through the paper with me and help me understand a couple things?

Yes, definitely!

bobbym · 2011-05-20 00:39:27

Hi mathlover002;

Welcome to the forum!

mathlover002 wrote:

i feel like a complete idiot, getting a question like that wrong.

That is good way to feel. If it hurts you will never forget it. More importantly you have learned something. You know what? That feeling of being kicked in the gut when you make a mistake never goes away, nor should it. That is how we learn. Just do not let it defeat you, everybody makes mistakes!

Take a look at my signature. It is from a famous countryman of yours. Follow his advice!

mathlover002 · 2011-05-20 00:50:28

hi guys,

this is the paper in question, i just uploaded it here.. http://www.2shared.com/document/p0Xh65EE/C1_May_2011.html

i forgot to say, i had already done part (b) where it said to find the sum of the sequence, haha. 100/k was pretty much half a guess, so i was relieved that i got it right...but then again it is a 2-marker so i would only get 1 out of 2.

If k is a factor of 100, then there would naturally be 100/k terms which are multiples of k.
Consider any of the factors:
[1, 2, 4, 5, 10, 20, 25, 50, 100]
If you take k=25, there would be 100/25 = 4 terms in the sequence.

hmm...i see, how can this be algebraically shown?

the truth is..i have wanted to sit this paper since year 9, and to not get 100 UMS at year 11 in c1 is a bit heartbreaking. hopefully i can learn from my mistakes..

for those who downloaded the paper, check out question 7) (c)...i got that one wrong, i think i know what the right solution is now though..i kept trying to find a VALUE of k, when the question didnt ask for that! so i got 0/2 there. i put in 'therefore f(x) = 0 has real solutions' because sometimes in m1 you get a mark just for writing something like that. but i think i know the solution now!

what do you guys think of the paper? i think i got 72/75 now...i hope that is good

again, thank you all for your lovely comments.

i have C2 exam on thursday 26th may, and C3 exam on 16th june (in 27 days)...haven't really started learning C3, i wonder if i can do it. it looks quite easy, i hopefully want to get it all covered in 13 days so i have 2 weeks leading up to the exam just to go through all the past papers...

for me, C3 will be more pressure because you have to get 180/200 in C3 and C4 combined to get A* in a-level maths...

thanks again for your replies!

mathlover002 · 2011-05-20 00:56:48

for anyone interested, here is the M1 may 2011 paper that i literally sat a minute after my c1 exam. i had exam clash so had to do both...had a headache afterwards, then followed by 2.5 hour english paper in the afternoon where the theme was on arguments for british people not going on holiday abroad. i just wanted to go to sleep.

http://www.2shared.com/document/RycQdENG/M1_May_2011.html - M1 paper

could someone go through 7) (c) (ii) with me? i got everything in the paper right except for that..luckily it was only a 2 mark question. thanks

Bob · 2011-05-20 01:16:18

hi mathlover002

M1 7cii

I have to do the earlier bits. Let me know of you agree with these:

OP = i + j + t(2i-3j)
OQ = -2j + t(3i + 4j)

=> PQ = PO + OQ = -i - 3j + t(i + 7j)

For due North:

want 'i' component to be zero

so - i = -ti => t = 1

so time will be 3pm

For North West

want i component to be some value, say , ki and j component to be same but opposite sign, ie -kj

so - 1 + ti = ki
and -3j + 7tj = -kj

so -1 + t = 3 - 7t => t = 1/2

so time is 2.30pm.

C1 7

b^2 - 4ac = (k+3)^2 - 4k = k^2 + 6k + 9 - 4k = k^2 + 2k + 1 + 8 = (k + 1)^2 + 8

For all k, (k + 1)^2 ≥ 0 so (k + 1)^2 + 8 > 0

=> there will always be two square roots of this expression => there will always be two roots to the equation

Bob

Last edited by Bob (2011-05-20 01:27:13)

gAr · 2011-05-20 01:30:02

Hi mathlover002,

...how can this be algebraically shown?

The only algebra I can think of is there already!
nk=100

Think of it this way: How many numbers between 1 and 100, inclusive, are divisible by k?
It's 100/k, isn't it?

mathlover002 · 2011-05-20 02:32:01

thanks...

for PQ, i got the same answer, but i multiplied it out and then collected the i terms and j terms together. would i still get the marks?

as for the quadratic question, that makes sense...i thought that would be the solution.

thanks for your posts!

so, what do you think the papers are like? easy, hard?

Bob · 2011-05-20 04:15:57

hi

would i still get the marks?

Yes. It asks for 'expressions' so either answer is ok.

Having looked at both papers I think they are about what I would have expected. On C1 I think 1-4 are just standard theory; 4,5,6 and 8 are about medium difficulty; 7, 9 and 10 are harder. That's what you ought to expect; the questions start easy and gradually get longer and harder. On M1 I think 1, 2, 4 and 5 are standard theory; the others are about medium difficulty.

I assume you've done GCSE a year early. It's a big step up to AS and A2; even some top GCSE students find it tough going. You won't be able to get by on talent alone; you'll need to put in the hours learning what is what. I've taught maths for 37 years. My brightest student had sailed through GCSE without really trying; he was very gifted. Then he tackled A level and found he couldn't do that any more. He had to stay in some nights and give up the part time job. But he got three grade As (no A* in those days) and went to Warwick to do their MORSE course. By now, I expect he is earning a fortune in finance.

You say you haven't started on C3 yet. Eeeekkk. That's leaving it a bit late. The degree of difficulty goes up with each new module. Don't want to frighten you off; I admire your determination; but I think you should start on it as soon as you can. By all means post here if you need help.

What's the situation teaching wise? Are you ahead of the rest of the class so the teacher has given you the books and said 'get on with it'? That's ok; I know plenty of students who manage that ... including myself as my A level teacher wasn't up to much. But you will need time to absorb the methods etc.

What else are you studying? Is your planned finish date two years hence or one? My son went to Cambridge for his maths degree, then Manchester for his PhD. If you have any questions about the University I'll pass them on.

Good luck with all your other exams,

Bob

Last edited by Bob (2011-05-20 04:18:58)

mathlover002 · 2011-05-20 04:45:10

hi,

no, i am doing my maths gcse this year too, but i have been getting either 99% or 100% in every past paper my teacher give me for gcse, so he said for me that he will enter me for C1, C2, C3 and M1.

to be honest...i dont struggle with maths that much. i started learning calculus bit by bit when i was about 13, when i was 14 i had, through experience, covered a lot of the a-level course (eg. some stuff about matrices, complex numbers, and others that come up in FP1-3). i taught myself C1 in a day, C2 in about 2 and a half days, and M1 took me 10 days to get to a point where i was happy with where my level was at.

i don't mean to sound boastful but C3 does not look difficult...i have looked at the specification, and past papers, all of it looks learnable in about 3 days. perhaps even 2. i know most of the trig identities through experience, plus topics like change of sign surprised me because i thought that that was obvious and didnt need to be taught in a module...i hope i don't eat my words on the C3 exam day.

basically, the plan is for me to join a year 13 class next year, where i will sit 8 modules to complete the further maths course. then i will sit the remaining 6 modules in year 13 to get a qual. in further maths additional. (modules like D2, M3, M4, M5, FP3, S4 which are not taught at my college)

thank you for your help! it is good to know that you are willing to help me at a time of urgency like exams. i would like to be a mathematician or physicist when i am older...hopefully i can get there.

to absorb the methods doesnt usually take me longer than half an hour (for a-level modules so far). i just do as many exercises as i can, eventually it clicks. hard to explain.

the reason mechanics took so long was because i didnt have access to a textbook at the time, so i had to self teach mostly from past papers and revision websites. in past papers i usually got between 70 and 75 consistently so i became confident i could do well.

i just need to go over c2 today and tomorrow, and the day before the exam, just to make sure i am still at the level i was before (where i could consistently get full marks in papers). i have half term in a couple of weeks so that should give me plenty of time for C3 preparation...

i have basically been self-teaching myself the modules entirely, my teachers dont run any kind of revision sessions for me to pop into. but they say i can come after school if i am struggling or anything. but at the moment its going fine - i am just a bit upset that i didnt get 75/75 in either paper (i got 72/75 in C1 and about 73 in M1 i think). i hope i dont have to retake..but looking at past papers that C1 paper is definitely harder than any previous ones. since it is harder than the paper where the grade boundary was 71/75 a couple years ago, maybe this one will be low too (in which case i will get 100 ums). m1, i doubt it will be less than 75. if i am lucky, 74. which means anywhere between 94-99 ums).

again, thank you for all your help, i will come to you for any help if need be

Math Is Fun Forum

#1 2011-05-19 22:30:03

depressed about c1/m1 maths papers...

#2 2011-05-19 23:09:22

Re: depressed about c1/m1 maths papers...

#3 2011-05-19 23:10:18

Re: depressed about c1/m1 maths papers...

#4 2011-05-19 23:21:07

Re: depressed about c1/m1 maths papers...

#5 2011-05-19 23:25:22

Re: depressed about c1/m1 maths papers...

#6 2011-05-19 23:50:24

Re: depressed about c1/m1 maths papers...

#7 2011-05-20 00:39:27

Re: depressed about c1/m1 maths papers...

#8 2011-05-20 00:50:28

Re: depressed about c1/m1 maths papers...

#9 2011-05-20 00:56:48

Re: depressed about c1/m1 maths papers...

#10 2011-05-20 01:16:18

Re: depressed about c1/m1 maths papers...

#11 2011-05-20 01:30:02

Re: depressed about c1/m1 maths papers...

#12 2011-05-20 02:32:01

Re: depressed about c1/m1 maths papers...

#13 2011-05-20 04:15:57

Re: depressed about c1/m1 maths papers...

#14 2011-05-20 04:45:10

Re: depressed about c1/m1 maths papers...

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