Mr M's OCR (not OCR MEI) Core 3 Answers June 2012

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Reply 40

sethacus2

Do you have any idea what the grade boundaries might be? Standard 58/72 for A?

Reply 41

Nugard123

Hmm I think at the minimum i got 60/72. Do you think that could be an A*? I think i'm on the borderline.

Reply 42

Mr M (jr)

Original post by Doctor.

you've been here all along and you have the paper, yet you didn't post it up?! :sigh:

Been busy teaching all day! I think FP2 and C3 done by 5pm having started at 3pm isn't bad going :indiff:

Reply 43

c_subs

Original post by MP1805

Exactly what I said to myself during the exam but, if we had paid attention ... the previous question was the answer to the integral of ln(2y).

I know, but I don't remember what that was, do you remember?
so what was the answer, or you mean the answer to Q8 was the answer to Q9?

Reply 44

Sweetcorn_1

Lost 4-8 marks in this paper, an improvement from the 20 something I lost in Jan 2012. I might meet my firm offer now if I can keep it up because M1 was a disaster.

Reply 45

MP1805

Original post by tomfails

Can anyone remember the first question, as in what was inside the modulus functions ?

2x - 5 > x + 1

Reply 46

Fusionary

Does anyone remember what you had to integrate for 4b? (and the limits were 1 and 0 I think?)

Reply 47

MP1805

Original post by c_subs

I know, but I don't remember what that was, do you remember?
so what was the answer, or you mean the answer to Q8 was the answer to Q9?

Sz for my misunderstanding. Anyways, the integral was like yln(2y) - y and then you would apply the limits to find the volume and I think you will get the same as Mr M.

Reply 48

Voglie

Original post by MP1805

53/72 is 73 UMS, however, considering how well others did there is no way it is going to lower and even if it does it wont lower by that much. In fact, I think that is like the grade boundaries for Jan 2012 and that C3 was exam was so hard.

Sorry for ruining your hopes but I want it to be an A as well as i got 53/72, if only my brain functioned for the volume question :frown:

But 54 was the highest an A has been in the last 5 papers.

Reply 49

MP1805

Original post by sethacus2

Do you have any idea what the grade boundaries might be? Standard 58/72 for A?

I usually take UMS as a percentage for standard predictions hence, I multiply by 100. In your case, according to me, that is an A on the dot, because: 58/72 * 100 = 80.5%. So, if the grade boundaries lower then you got your A.

Reply 50

Sweetcorn_1

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 3 Answers June 2012

8. (i)

5 \sin (\theta + 53.1301)

(3 marks)

(ii) (a) -64.7 degs and 138 degs (4 marks)

(b) k = 8 and c = 3 (4 marks)

For 8(ii) I got two negative answers and for (iii) I got k wrong but c=3 because I thought the max/min was +-7.

How many marks would I lose :frown:

And do you think the grade boundaries are as high as everybody says they will be?

thx

Reply 51

Mr M

Study Forum Helper

Original post by tahseen1995

What I meant is I correctly rearranged the equation to get pi times the integral of y=ln(2x) with limits of 1/2e^(4) and 1/2, but instead of using part (i) of question 9 to find the integral of ln(2x) I integrated ln(2x) to 1/x (I panicked due to lack of time) and went from there.

I was wondering if would at least get a mark for correctly rearranging the equation and realising the the area of the shaded region rotated about the y axis would be the integral of ln(2x) within limits of 1/2e^(4) and 1/2 multiplied by pi.

...did I make sense?

lol thank you

Yes 2 or 3 marks for knowing that.

Reply 52

MP1805

Original post by Voglie

But 54 was the highest an A has been in the last 5 papers.

Wow ... Thanks for that. You have put my hopes up again. So I guess we do have a chance after all. :smile:

Reply 53

IBrennan

Original post by MP1805

Mr M or anyone who can tell my why I am wrong:

4)B) I used the chain rule so,

I let u= e^x + 2 so dx/du gives me 1/e^x
Then, I integrated u^2 = u^3/3
Multiplying both I got ((e^x + 2)^3)/3e^x
Applying the limits my answer was: (e + 2)^3/3e - 9

I would really appreciate it, if you could tell me how many marks I would get, if any. Thank you.

This is exactly what I did! It didn't even cross my mind that it was wrong until i checked on here, i praying we get some method marks?!

Reply 54

Sweetcorn_1

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 3 Answers June 2012
1234

8. (i)

5 \sin (\theta + 53.1301)

(3 marks)

(ii) (a) -64.7 degs and 138 degs (4 marks)

(b) k = 8 and c = 3 (4 marks)

For 8(ii) I got two negative answers and for (iii) I got k wrong but c=3 because I thought the max/min was +-7.

How many marks would I lose :frown:

And do you think the grade boundaries are as high as everybody says they will be?

thank you

Reply 55

Mr M

Study Forum Helper

Original post by leej11

How many marks would I lose for getting

k = 3/5
c = 40

Because I read the question as 37 not MINUS 37!

Ouch. I think you will get 2 marks.

Reply 56

Voglie

Original post by MP1805

Wow ... Thanks for that. You have put my hopes up again. So I guess we do have a chance after all. :smile:

Let's hope for the best bro! :wink:

Reply 57

MeatyBeast

Qu 5i) I drew a negative quadratic graph with a y intercept of + 14 and a lnx graph and showed they only intersect once. Is this correct?
8iia) How many marks would I lose, i got 138 degs but I stupidly did +11.1 - 53.1 not -11.1 - 53.1 so I got one of the answers wrong

Stupidly lost another 4 marks by not integrating correctly :mad: