Arsey's C3 Edexcel 25th Jan 2013 Model Answers Thread (attached to first post)

(Originally Posted by kvohra)
Hi arsey, for question 6iib) it said that the answer obtained in part iia) is equal to 1 so the answer would be different?


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yeah i really want to know aswell

Hi arsey, can understand that you must ge getting a lot of questions but I was wondering if I will still get full marks for leaving 8b) as (-ln(1/2)/0.25) since it equals the same thing??

Hey Arsey for the range question i forgot to put 0<h(x) and just left the (h)<=1/root5. Also for 2c) I did not put the coordinates for the origin, how many marks do you think those would those cost me?

They are both equal to 0, you are rearranging ii(a).

Here are my model answers

The Core 3 paper wasn't anywhere near as bad as I expect some of you think it was. There were a couple of nightmare parts to questions but most of it was fairly standard and a well prepared candidate should have been able to achieve a decent mark out of 75.

Q1 Differentiation a) easy b) pretty easy - 7 marks (all okay)


Q2 Numerical methods a) easy (you don't need the bit I did in square brackets) b) easy - 8 marks (all okay)


Q3 Transforming graphs. This was a pretty easy question - 9 marks (all okay)


Q4 Trigonometry a) very easy, it is on virtually every paper b) This is pretty hard, understanding what to choose to lead to the maximum of p wasn't easy - 8 marks (4 easy, 4 hard)

Q5 Differentiation. Pretty easy, the proof was fairly easy - 11 marks (all okay)


Q6 i) Trigonometry i) I think this will be poorly answered but it is pretty easy ii) and b) easy - 11 marks (all okay)


Q7 Algebraic fractions and differentiation. Fairly easy - 12 marks (all okay)


Q8 Differentiation a) stupidly easy b) very hard - if you got this right, well done c) reasonable - 9 marks (5 okay - 4 hard)


So I think there are 8 hard marks that anyone taking the exam will have done well to get right.

In terms of boundaries I would be guessing at

52 = 70ums
59 = 80ums
66 = 90ums
73 = 100ums

For 8b would they accept " - 4 ln (1/2) "? Or would it only get 3/4

If I've been constantly getting 97% average in every single past paper and SOLOMAN papers and I found this paper difficult in terms of getting 100% then surely the A* grade boundaries should be at 66marks. It's ridiculous the amount I've studied and ended up getting **** on by the old wrinkly edexcel team, I mean look at the previous papers they might have slightly difficult question but atleast they are answerable to attain 100ums unlike question 8b). People who got 90 ums or more in the previous years don't mean nothing. *rant over*

I actually managed to get the answer to 8b) by working on it for half an hour, until I got an answer 2.67.... and then I plugged it in and it was close to the answer so I just thought it must be ln something close to 2.67... so I guessed 4ln(2) and plugged it in and I almost cried when it came to 9500

But then I just realised that I got the range question wrong because I put between 0 and root5 (forgot to sub it into the h(x) to get the range but I showed all the working). And also on the trig one I was stupid and put 0,30,150,360 instead of 0,30,150,180. Also on the first question where it said put it in the form y=mx+c I may have put it as mx + y + c = 0 but I got the equation right.

How many marks total will I have lost? I'm hoping no more than 5

I think you got Question 8 b wrong.