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# Mr M's OCR (not OCR MEI) Core 2 Answers May 2013 watch

1. (Original post by HayyanN)
Attachment 216877Don't ask me why, but for some stupid reason this is what I put for 7 ii. Is it worth any marks ? :/
thanks
I don't think so
2. (Original post by hayhayhay1)
for question 4, if i had +c on the ends would that still be okay
and for the trapezium rule one (1) if i used the values of x=5,7,11 (forgot 9) and done everything else right and came out with 4.56, how many would i drop ?
No problem with + c

drop 2 marks for trapezium rule
3. (Original post by Shuster)
Hi,
For the question with the tangent, i worked out the gradient of the tangent to be 4, instead of 3. I then proceeded correctly, found the equation of the tangent ect.. How many method marks do you think I will get? Thanks.
I think you will lose 2 accuracy marks
4. (Original post by Shuster)
For the very last question, iii) i didn't have time to finish so i only wrote down 2 of the possible 3 values. Will i only lose one mark?
yes
5. (Original post by Mr M)
1) drop 1 mark

6i) drop 1 or 2 marks

8c) drop 1 mark

9i) This is fine
Thanks very much - that's a bit of a relief. I thought I would have lost at least 2, 2, 1 and 1 respectively for those answers xD
6. (Original post by Mr M)
No problem with + c

drop 2 marks for trapezium rule
thank you very much
7. Hi Mr M, just a quick few questions:

For 7(ii) is wasn't sure what to do so I wrote out the y-y1=m(x-x1) formula.
Then I calculated an answer for area under the tangent as a triangle (0.5 x base x height) which is incorrect.
Then Area of Triangle subtract Integration area given.
Any method marks gained here?

Also, 8(iv) Logs Question,
I got b=2/a
a^x = 4b^x
XLog2a = xlog2(4(2/a))
Xlog2a = xlog2(4) + xlog2(2) - xlog2(a)
Xlog2a = 2x - xlog2(a)
At which point i stopped.

Any marks gained here?
Thanks so much for the help!

Posted from TSR Mobile
8. (Original post by Mr M)
Mr M's OCR (not OCR MEI) Core 2 Answers May 2013

1. 6.39 (4 marks)

2. (i) 254 and 106 degrees (3 marks)

(ii) 71.6 and 252 degrees (3 marks)

3. (i) (4 marks)

(ii) c = - 11 (3 marks)

4. (a) (3 marks)

(b) (i) (2 marks)

(ii) a = 2 (3 marks)

5. (i) 62.2 (4 marks)

(ii) 34.0 (4 marks)

6. (i) 963 (3 marks)

(ii) 17 (6 marks)

7. (i) Show ... (4 marks)

(ii) (5 marks)

8. (i) (a) (0, 1) (1 mark)

b) (0, 4) (1 mark)

c) Any value where a > 1 and any value where 0 < b < 1 (2 marks)

(ii) Show ... (5 marks)

9. (i) 15 (2 marks)

(ii) Show f(-0.5)=0 and (6 marks)

(iii) and and (4 marks)

I'll be around a bit this afternoon and then part of this evening to answer questions. Please post in this thread rather than sending me private messages.
Hey Mr. M, thanks for the answers.
In question 4 I wrote +c instead of +k for the constant, does that mean I'll drop marks?
In question 8c) I said a=1, b=1/16 would a=1 be correct? You wrote a>1.
Finally (sorry for all the questions!) in question 9ii I divided f(x) by (2x+1) rather than showing f(-1/2)=0 and for some reason went on to get f(x)=(2x+1)^2(x+1), how many marks do you think I'd lose?

Thank you very much,
Amy
9. (Original post by amy.2209)
Hey Mr. M, thanks for the answers.
In question 4 I wrote +c instead of +k for the constant, does that mean I'll drop marks?
In question 8c) I said a=1, b=1/16 would a=1 be correct? You wrote a>1.
Finally (sorry for all the questions!) in question 9ii I divided f(x) by (2x+1) rather than showing f(-1/2)=0 and for some reason went on to get f(x)=(2x+1)^2(x+1), how many marks do you think I'd lose?

Thank you very much,
Amy
10. Hi Mr M, thanks for the answers!
Made a few silly slips, but I think I did okay! I have a few questions:

I accidentally found the perimeter for 5ii for the entire shape and not for BDC, will I gain any method marks?

For the integration question 7ii, I used y-y1=m(x-x1) to find the tangent, then integrated this and put the values of 4 and 5/2 into it. Then subtracted to get a positive area. Would I gain any method marks for this or is it completely incorrect?

I was also wondering whether you would have any idea of the grade boundaries?

Thank you!
Bethany
11. Mr M,

For question 2 I wrote my answers all to one decimal place instead of 3sf like you did, will I drop marks?
Also, for 9 part 2 I factorised it but didnt fully factorise the quadratic, how many marks would I lose?
Finally, for the area under the curve I explicitly stated that you had to use area of triangle but couldn't work it out, would I gain a mark?
Thanks
12. Hi Mr M,

I was just wondering, I did the Logs question a little bit differently to everyone else, but still got the same answer, but I was just wondering, do you get method marks for applying the Log laws in your working out?
Thanks.
13. (Original post by Mr M)
Mr M's OCR (not OCR MEI) Core 2 Answers May 2013
7. (i) Show ... (4 marks)

(ii) (5 marks)

9. (i) 15 (2 marks)

(ii) Show f(-0.5)=0 and (6 marks)

(iii) and and (4 marks)

I'll be around a bit this afternoon and then part of this evening to answer questions. Please post in this thread rather than sending me private messages.
For 9iii, I got 4 values but 3 of my values are correct. How much marks do I get for that question?
And for 7ii, I found out the area of the triangle under the line and then minused 9.5 from the area of triangle and got something like 1.1. I know this is wrong but how much marks would I get for calculating the area of triangle (if that was needed)?
14. (Original post by SinghSTAR)
Hi Mr M, just a quick few questions:

For 7(ii) is wasn't sure what to do so I wrote out the y-y1=m(x-x1) formula.
Then I calculated an answer for area under the tangent as a triangle (0.5 x base x height) which is incorrect.
Then Area of Triangle subtract Integration area given.
Any method marks gained here?

Also, 8(iv) Logs Question,
I got b=2/a
a^x = 4b^x
XLog2a = xlog2(4(2/a))
Xlog2a = xlog2(4) + xlog2(2) - xlog2(a)
Xlog2a = 2x - xlog2(a)
At which point i stopped.

Any marks gained here?
Thanks so much for the help!

Posted from TSR Mobile
7ii) you will get one mark for subtracting a triangle, maybe more if you are lucky

8iv) 1 or 2 marks for that I should think
15. (Original post by Mr M)
yes
Hi Mr M
On 3i) I wrote it in this order: 6000x^2 + 960x + 64 instead of '64 + 960x + 6000x^2
Wil I lose any marks?

And on 4b i) when integrating I wrote -12x^-2 + k. And then put the x^2 on the bottom to make -12/x^2. + k. Will I still get all the marks for this?

So worried
16. (Original post by amy.2209)
Hey Mr. M, thanks for the answers.
In question 4 I wrote +c instead of +k for the constant, does that mean I'll drop marks?
In question 8c) I said a=1, b=1/16 would a=1 be correct? You wrote a>1.
Finally (sorry for all the questions!) in question 9ii I divided f(x) by (2x+1) rather than showing f(-1/2)=0 and for some reason went on to get f(x)=(2x+1)^2(x+1), how many marks do you think I'd lose?

Thank you very much,
Amy
Of course +c is fine

a = 1 is wrong (drop 1 mark)

9ii the division is fine but the rest is wrong, I can't tell you how much that might be worth as it depends on whether any of the working is right
17. (Original post by bethanyr)
Hi Mr M, thanks for the answers!
Made a few silly slips, but I think I did okay! I have a few questions:

I accidentally found the perimeter for 5ii for the entire shape and not for BDC, will I gain any method marks?

For the integration question 7ii, I used y-y1=m(x-x1) to find the tangent, then integrated this and put the values of 4 and 5/2 into it. Then subtracted to get a positive area. Would I gain any method marks for this or is it completely incorrect?

I was also wondering whether you would have any idea of the grade boundaries?

Thank you!
Bethany
5ii) you will get a mark for finding the arc length at least

7ii) you can do that but your lower limit is wrong - you will get a couple of method marks

18. (Original post by TSR29)
Mr M,

For question 2 I wrote my answers all to one decimal place instead of 3sf like you did, will I drop marks?
Also, for 9 part 2 I factorised it but didnt fully factorise the quadratic, how many marks would I lose?
Finally, for the area under the curve I explicitly stated that you had to use area of triangle but couldn't work it out, would I gain a mark?
Thanks
2) yes in some cases e.g. question 1 you will lose marks

The question paper says "Give non-exact numerical answers correct to 3 significant figures unless a different degree of accuracy is specified in the question or is clearly appropriate". They don't mind if you are more accurate than this.

9 part 2) drop 1

area) you *might* get a mark
19. (Original post by VivDid)
Hi Mr M,

I was just wondering, I did the Logs question a little bit differently to everyone else, but still got the same answer, but I was just wondering, do you get method marks for applying the Log laws in your working out?
Thanks.
There are many ways to obtain the correct answer. Any correct approach will get full credit.
20. (Original post by TwlilightLoz)
For 9iii, I got 4 values but 3 of my values are correct. How much marks do I get for that question?
And for 7ii, I found out the area of the triangle under the line and then minused 9.5 from the area of triangle and got something like 1.1. I know this is wrong but how much marks would I get for calculating the area of triangle (if that was needed)?
drop 1 for the extra trig answer

you might get no marks for that, it really depends on whether any part of your working was valid

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