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C1 Jan 2012 Edexcel - Post exam discussion - Solutions and paper in first post

I think I will create two types of thread a pre-exam and post exam thread.

Pre-exam threads understandably need to be locked, but it seem to take ages for them to be unlocked.

Here are my model answers, written on the paper. I thought it was a hard paper in comparison to previous ones.

How did you find it?

Q1. Fairly standard calculus question. (6m)

Q2. Pretty easy Surds (6m)

Q3. Easy inequalities (6m)

Q4. Standard iteration sequences (6m)

Q5. a) unusual qu will cause probs (4m)

Q5. b) standard sketching (4m)

Q6. Coordinate geometry, not easy but fairly standard (7m)

Q7. Easy standard calculus question (5m)

Q8. Fairly tricky sketching / transforming question. First 5 marks were easy though. (10m)

Q9. Quite an odd AP question, lots of errors will be made on this qu (9m)

Q10. Calculus/Coordinate geometry again, this one will cause many probs too (11m)


So I do think it was a harder than normal paper but not stupidly hard. The first 24 marks should be bankers, I would say there were 40-45 pretty easy marks. So I would not expect very low boundaries.

Guessing boundaries is far from easy; Jan C1 boundaries are typically higher than those in June. More entries in June, more students retaking... only once has the boundary for an A dipped below 60 for an A in the past C1 Jan papers.

C1 Jan 11 was definitely easier and that was 62 for an A.

I am going to go for

100UMS = 73
90UMS = 66
80UMS = 59
70UMS = 52
60UMS = 45
50UMS = 38
40UMS = 31
(edited 12 years ago)

Scroll to see replies

Reply 1
do you think grade boundaries will be lower this year
Reply 2
Arsey you know where you had that the two equation which said it cannot intersect or something like that, but in your solution you used the discriminant but all i said was that 2x2..... cannot be factorise. How many marks do you think i lost?
Reply 3
Original post by Arsey

Original post by Arsey
I think I will create two types of thread a pre-exam and post exam thread.

Pre-exam threads understandably need to be locked, but it seem to take ages for them to be unlocked.

Here are my model answers, written on the paper. I thought it was a hard paper in comparison to previous ones.

How did you find it?


Hi, for 9(b) I did the correct working for everything except I didn't multiply 1800 by 5, therefore getting the wrong value for T.

I then used this value in 9(c) using the same method as you but obviously got a different answer.

How much do you think I will be penalised for doing this?

Sorry if I double posted this but wanted to make sure it was in the right place.
Reply 4
I guess this is the offical thread so I will re-post..

q1-4 fine

I remember changing my curve drawing for q5 and got that right. On the same question you know when it says use algebra to show C & L don't intersect, can you use the quadratic equation and say that you can't sqroot the negative number..?

Didn't finish q7, I got C but forgot to sub in x=1 to find the final value.. Damn

I didn't get 8 part d but knew it had something to do with moving 2 to the right.. will that get me the marks just drawing a translation of +2 horizontal?

for q9 I think I got b and c wrong.. I somehow got my numbers wrong and couldn't work out the values of T and P. i ended up with something like t=81000/18 and I just forgot what to do even though that is wrong anyway.

think I got q10 right thank god but I did part b in reverse somehow to get the gradient by rearranging the equation they tell you to proove and inverse the gradient. i could then work out how to do it then.

I think I will get around 63-65/75.
Reply 5
i think i got between 55-60, did you have to use b2-4ac<0 to prove that the line and quadratic line didn't intersect
How many marks would I lose for getting my sums wrong in the surd question part b and not dividing by 7 Arsey? I was thinking I'd get 1/2 marks for the working out.
Reply 7
Will plow through the how many marks have I lost posts tomorrow.
Reply 8
I got my method right for finding T but had a division error that is 18000/45=40 instead of 400 i just used that value 40 value to find P. Does that mean that error is carried forward or not.
Reply 9
Original post by Natty.B
i think i got between 55-60, did you have to use b2-4ac<0 to prove that the line and quadratic line didn't intersect


No, you just had to use algebra which meant you could show rooting a negative doesn't give a real value.
Reply 10
i've seen in other papers that leaving the area as a fraction is fine, however i left the area as 104/6 instead of cancelling to 52/3, would this be one mark lost or would i still be ok for the three marks?
Reply 11
I wrote two answeres for the calculating the area, one is correct, and one is incorrect, do u think they give me the mark or no???
Original post by Arsey
Will plow through the how many marks have I lost posts tomorrow.

Okay, how many marks would you lose (just for question 9) if you did this:

Original post by sarif1
I got my method right for finding T but had a division error that is 18000/45=40 instead of 400 i just used that value 40 value to find P. Does that mean that error is carried forward or not.


As I did exactly the same thing (I mean exactly - I did the same calculation wrong in the same way).
How many marks would be lost just for this error?
Reply 13
anyone got grade boundaries yet?
Reply 14
Where I lost marks:
forgot to rationilise (4 marks)
didnt state there was no real roots/negative couldnt be squared (3 marks)
didnt add up right for the area of the triangle got 16 not 17 1/3 (3 marks)
lost 4 marks on 10c - not enough time
yeah so i lost alot of marks, hopefully low grade bounaries
Reply 15
Original post by Natty.B
do you think grade boundaries will be lower this year


it should be...:s-smilie::s-smilie:
WOW!!!

I F'ed up real bad.
Looking At the model answers, I realise that it didn't go as well as I thought it might have.

Not looking forward to results day. And now I'm feeling worse about C2. l

I wish most of the questions I did in the past papers came up, they seemed so much easier.
Original post by Arsey
Will plow through the how many marks have I lost posts tomorrow.


Well in that case :colondollar:

For question 3b) I factorised the inequality , put it into double brackets ... But my answer at the end, for whatever reason, was for when x<0 rather than x>0
So it was -2<x<6

For question 6c) I didnt fully simply my answer, it was still 104/6

And for question 8d) I forgot to put the y intercept coordiante , but both my x intercept coordinates were correct



THANK YEWWW , MUCH APPRECIATED :colone:
Original post by Arsey
I think I will create two types of thread a pre-exam and post exam thread.

Pre-exam threads understandably need to be locked, but it seem to take ages for them to be unlocked.

Here are my model answers, written on the paper. I thought it was a hard paper in comparison to previous ones.

How did you find it?


Arsey you are a don nice one on gettin the paper
for the one where u have to show tht they dont intersect you have to equal the two equations together and they shouldnt equal by sub ing in x

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