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Mr M's OCR Core 1 (not OCR MEI) May 2016 Answers

Mr M's OCR (not OCR MEI) Core 1 May 2016 Answers


1. (i) 2x292x^2-9 (2 marks)

(ii) -10 (2 marks)


2. 14+354-\frac{1}{4}+\frac{3\sqrt5}{4} (4 marks)


3. x=3x = -3 and y=5y = -5 or x=35x = \frac{3}{5} and y=295y = \frac{29}{5} (5 marks)


4. y=116y=\frac{1}{16} or y=81y=81 (5 marks)


5. (i) 262^{-6} (2 marks)

(ii) 21332^{\frac{13}{3}} (3 marks)


6. (i) 2(x3)2+22-2(x-3)^2 + 22 (4 marks)

(ii) (3, 22) (2 marks)


7. (i) Negative cubic with the x axis as a tangent at (0, 0) and crossing the x axis at (3, 0) (3 marks)

(ii) y=(x2)2(5x)y=(x-2)^2(5-x) (2 marks)

(iii) Stretch parallel to the y axis scale factor 0.5 (2 marks)


8. (i) Show ... (3 marks)

(ii) The gradient at A is 20 and as h approaches 0 the gradient of the line also becomes 20 (1 mark)

(iii) 2014\frac{201}{4} (3 marks)


9. k<2k<-2 or k>5k>5 (7 marks)


10. (i) Centre (4, 3) Radius 353\sqrt{5} (3 marks)

(ii) y=2x20y=2x-20 (6 marks)

(iii) y=2x+10y=2x+10 (3 marks)

(iv) 0<r<3550<r<3\sqrt{5}-5 (2 marks)


11. a=27a=27 (8 marks)


This was definitely the most difficult Core 1 ever. I'll be around to discuss questions later for a bit. Post in the thread, don't private message me as the system is running very slow.
(edited 7 years ago)

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the answer for question 5 part 2 is 2^13/3 not 2^13/2
Reply 2
Thanks for the speedy answers.

I have a few queries;
for question 3. I got x=-3 as opposed to x=3
for 5ii I got 2^(13/3) maybe I made a mistake
on 8ii I put "The gradient of AB when h=0 is 20. The gradient of the curve when x=5 (at A) is equal to 20." how many marks would you say this got (if any!)?
would I still get full marks for 8iii for 1005/20 (which = 201/4)?
10iv I only put r<3(sqrt(5))-5 so I guess I lost a mark there

Thanks for spending your time to answer
Original post by TheSurrealTV
the answer for question 5 part 2 is 2^13/3 not 2^13/2


Thanks for spotting the typo. I'll fix it now.
I messed up the quadratic substitution question - rushed through it and accidentally put let y=1/2x instead of y=1/4x.

Will i get any marks out of 5 for this?

Also for radius question I put r<=3sqrt(5)-5 would that be 1/2 marks?

Thanks for the quick mark scheme.
(edited 7 years ago)
Reply 5
Original post by joejoeob
its (1-X) to 7)ii)


https://gyazo.com/1fc8fc02d2bdbc6d4a0ec7b798c25e09 I am pretty sure Mr M is right
Original post by duncant
Thanks for the speedy answers.

I have a few queries;
for question 3. I got x=-3 as opposed to x=3
for 5ii I got 2^(13/3) maybe I made a mistake
on 8ii I put "The gradient of AB when h=0 is 20. The gradient of the curve when x=5 (at A) is equal to 20." how many marks would you say this got (if any!)?
would I still get full marks for 8iii for 1005/20 (which = 201/4)?
10iv I only put r<3(sqrt(5))-5 so I guess I lost a mark there

Thanks for spending your time to answer


Q3. You are right. Typo again.

Q5ii. You are right.

8ii. Full marks.

10iv. Depends on how harsh they are. I *think* you will lose 1.
Reply 7
Original post by joejoeob
its (1-X) to 7)ii)


I got that as well.
Reply 8
Original post by Mr M
Mr M's OCR (not OCR MEI) Core 1 May 2016 Answers


1. (i) 2x292x^2-9 (2 marks)

(ii) -10 (2 marks)


2. 14+354-\frac{1}{4}+\frac{3\sqrt5}{4} (4 marks)


3. x=3x = -3 and y=5y = -5 or x=35x = \frac{3}{5} and y=295y = \frac{29}{5} (5 marks)


4. y=116y=\frac{1}{16} or y=81y=81 (5 marks)


5. (i) 262^{-6} (2 marks)

(ii) 21332^{\frac{13}{3}} (3 marks)


6. (i) 2(x3)2+22-2(x-3)^2 + 22 (4 marks)

(ii) (3, 22) (2 marks)


7. (i) Negative cubic with the x axis as a tangent at (0, 0) and crossing the x axis at (3, 0) (3 marks)

(ii) y=(x2)2(5x)y=(x-2)^2(5-x) (2 marks)

(iii) Stretch parallel to the y axis scale factor 0.5 (2 marks)


8. (i) Show ... (3 marks)

(ii) The gradient at A is 20 and as h approaches 0 the gradient of the line also becomes 20 (1 mark)

(iii) 2014\frac{201}{4} (3 marks)


9. k<2k<-2 or k>5k>5 (7 marks)


10. (i) Centre (4, 3) Radius 353\sqrt{5} (3 marks)

(ii) y=2x20y=2x-20 (6 marks)

(iii) y=2x+10y=2x+10 (3 marks)

(iv) 0<r<3550<r<3\sqrt{5}-5 (2 marks)


11. a=27a=27 (8 marks)


This was definitely the most difficult Core 1 ever. I'll be around to discuss questions later for a bit. Post in the thread, don't private message me as the system is running very slow.


It is possible for you to show questions. Much appreciated
Original post by joejoeob
its (1-X) to 7)ii) not (5-X)


No.

3(x2)=5x3-(x-2)=5-x
Original post by SGHD26716
It is possible for you to show questions. Much appreciated


I'm a bit busy to be honest. Ask your teacher to show you a paper tomorrow?
I think I got 71/72. I put that the radius is 0<r<2 instead of 0<r<sqrroot5 -5 so I think i will loose 1 mark for that
Original post by SGHD26716
I got that as well.


The answer I provided is correct here.
Original post by TheSurrealTV
I think I got 71/72. I put that the radius is 0<r<2 instead of 0<r<sqrroot5 -5 so I think i will loose 1 mark for that


Well done. Yes you will lose one for that.
Original post by ComputeiT
PLEASE HELP:
I messed up the quadratic substitution question - rushed through it and accidentally put let y=1/2x instead of y=1/4x.
Solved the quadratic to get the values of y as 1/2 and 3 but then because of writing 1/2x i squared them to get 1/4 instead of 81 (I know - massive moment of stupidity!).
Will i get any marks out of 5 for this?

Also for radius question I put r<=3sqrt(5)-5 would that be 1/2 marks?

Thanks for the quick mark scheme.


Probably 3 marks and 1 mark respectively.
Original post by Mr M
Well done. Yes you will lose one for that.


okay thanks for all your work
For the last question I got 18root27/12 which is 27 will I get full marks still or not? Thanks very much for doing this so quickly it's a great help:smile:
Original post by Mr M
Probably 3 marks and 1 mark respectively.

Thank you very much!
Original post by Bobby21231
For the last question I got 18root27/12 which is 27 will I get full marks still or not? Thanks very much for doing this so quickly it's a great help:smile:


As that question is worth 8 marks, I think you will lose 1 for failing to simplify.

And you are welcome.
Original post by finn.thehuman
For question 4, I got X=1/16 or 81. Have I read it wrong?


Yes but don't worry. Full marks.

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