C4 June 2012 - Post Exam Thread - Paper and Solutions in the FIRST POST

Scroll to see replies

Have done exactly the same mistake, I got lambda as 6 because I stupidly said that 24/6 =6 .... You probably have done the same >_< I hope we won't lose more than 1-2marks on this...

Oooh shiiiiiit, that horrendous piece of working does look similar!

Reply 281

sceptic_medic

Yeh the method marks would but not the subsequent accuracy marks

Reply 282

ChemistryKing

On question 3 when I did the binomial expansion, I stupidly had my 'n' value = 1/2 instead of -1/2 .. I did the reast of the question correctly though! How many marks would I lose for this?

Reply 283

Ihatemaths1

Original post by NutterFrutter

63/75 for an A, slightly lower than what Arsey is predicting.

He predicted 58 for an A

Reply 284

Who_Is_It?

Original post by ChemistryKing

On question 3 when I did the binomial expansion, I stupidly had my 'n' value = 1/2 instead of -1/2 .. I did the reast of the question correctly though! How many marks would I lose for this?

I made a stupid mistake on the binomial too, I misread it as -1 instead of -1/2 :s-smilie:

Like you my method was perfect and i done the next two parts correct.

Not sure how many marks we'll lose cause looking at previous mark schemes they only award 1 or 2 method marks and the rest accuracy marks for an expansion :frown:

I really don't know how they'll mark it...

Hope there is follow through marks for the two other bits though!!

Reply 285

Akbar2k7

I am kind of worried I need a C to get my overall B cause I think I got A in S1. I did nearly all the right techniques in this paper but my answers for alot of the questions where wrong especially the stupid Ln ones :/ nothing I can do now the fact Arsey thinks the grade boundaries are not gonna be sky high gives me hope did not enjoy this paper. Heres hoping i get my B overall in maths.

Reply 286

ChemistryKing

Original post by Who_Is_It?

I made a stupid mistake on the binomial too, I misread it as -1 instead of -1/2 :s-smilie:

I really don't know how they'll mark it...

Hope there is follow through marks for the two other bits though!!

Hopefully it'll say the rest of the marks can be obtained by doing it right using their 'n' .. Yeah there should be follow through marks for that I think

Reply 287

Who_Is_It?

Original post by ChemistryKing

Hopefully it'll say the rest of the marks can be obtained by doing it right using their 'n' .. Yeah there should be follow through marks for that I think

We can only hope, but i think it's unlikely cause they've never done it before :frown:

Also, all the examiners reports say that algebraic errors are heavily penalised in expansions, but because ours is a numerical error we might get one or two :s-smilie:

Can't believe I made such a stupid error. That one numerical slip could be the difference between an A and an A* for me and I'm raging!! :angry:

Might check with arsey to get more clarification on it??

Reply 288

Who_Is_It?

Original post by Arsey

Overall I thought it was a fairly standard paper, with a few tricky parts

Q1.

the need to sub in another value (x=1) could cause problems, which would be a disaster for part b). If a) was correct b) was reasonable

Q2.

Very straight forward, but rates of change often cause problems

Q3.

a) was fairly easy but b) and c) were odd

Q4.

Very easy separation of variables

Q5.

a) straight forward implicit differentiation but b) was tricky

Q6.

a) and b) were fairly easy but c) will cause a lot of problems

Q7.

unusual not to have the table drawn, may throw some people. b) was fairly straight forward although ln questions are odd.

Q8.

Straightforward vectors

It has been 52, 58, 58, 57, 58, 60, 61 for 80ums in the previous June sessions for C4

I would guess at the following boundaries

72 = 100ums
65 = 90ums
58 = 80ums
51 = 70ums
44 = 60ums
37 = 50ums
30 = 40ums

This thread will be locked at somepoint and then unlocked following the Core 4 examination. I will upload the paper and my solutions to this post in the morning following the exam.

I will do my best to answer questions about the paper but please try to read the thread first so that I am not answering the same questions lots of times.Here are some links to previous D1 threads, they are worth a read and you will see what the common errors were...

C4 Jan 2012 - http://www.thestudentroom.co.uk/showthread.php?t=1865949

C4 June 2011 - http://www.thestudentroom.co.uk/showthread.php?t=1619107&post=39

(Scroll to post #39)

Hey arsey thanks for your solutions!! You've helped me a lot over the past two years too and I'm very grateful :biggrin:

Can you answer a quick question for me please?
In my expansion I used the power of -1 instead of -1/2 (a complete stupid misread!!) I was wondering on how they mark expansions and how many marks would i expect to lose? And could I expect follow through marks for the next two parts using my incorrect expansion?? My method was perfect through the entire question, I just misread the power :frown:

Reply 289

oHellno

I thought it was a fair paper, but SO many people I spoke to found it awful so grade boundaries might be low? We'll see.

Reply 290

kanasaki

Anyone got lambda = 3 as I am using the other position vector for the equation and I come out with the same answer for the position vector of P

Reply 291

ss13

Original post by Phenylethylamine_

Hey Arsey - I got the partial fractions correct except the value of B, did everything right, subbed x = 1 but a simple arithmetic error cost me to get B = -3/2

I got values of A and C correct and so integrated as normal with the limits. Does the error get carried forward? How many marks out of 6 will I get for the second part? I know I lost an accuracy mark on part (a) so that's 3/4

i second this. what sort of marks would i lose for getting B wrong in part a) if my integration for part b) is correct, but im integrating the wrong thing?

Reply 292

accountant-future

I hated this paper personally and it's given me doubts overall

In all honesty, I need only DDE in my 3 remaining full A levels to achieve the extra 160 points to bring my total to 260 to get into my chosen uni

These are my results so far;

Core 1 - A
Core 2 - C
Decision - B
Core 3 - C
Stats - ? (Probs C/D)

Say if I get something really poor (like 20/75 on this paper)

Does that still make it good enough to get a D/E overall?