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

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


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

    (ii) -10 (2 marks)


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


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


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


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

    (ii) 2^{\frac{13}{3}} (3 marks)


    6. (i) -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=(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) \frac{201}{4} (3 marks)


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


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

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

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

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


    11. a=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.
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    the answer for question 5 part 2 is 2^13/3 not 2^13/2
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    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
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    (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.
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    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.
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    (Original post by joejoeob)
    its (1-X) to 7)ii)
    https://gyazo.com/1fc8fc02d2bdbc6d4a0ec7b798c25e09 I am pretty sure Mr M is right
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    (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.
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    (Original post by joejoeob)
    its (1-X) to 7)ii)
    I got that as well.
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    (Original post by Mr M)
    Mr M's OCR (not OCR MEI) Core 1 May 2016 Answers


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

    (ii) -10 (2 marks)


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


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


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


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

    (ii) 2^{\frac{13}{3}} (3 marks)


    6. (i) -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=(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) \frac{201}{4} (3 marks)


    9. k&lt;-2 or k&gt;5 (7 marks)


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

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

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

    (iv) 0&lt;r&lt;3\sqrt{5}-5 (2 marks)


    11. a=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
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    (Original post by joejoeob)
    its (1-X) to 7)ii) not (5-X)
    No.

    3-(x-2)=5-x
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    (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?
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    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
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    (Original post by SGHD26716)
    I got that as well.
    The answer I provided is correct here.
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    (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.
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    (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.
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    (Original post by Mr M)
    Well done. Yes you will lose one for that.
    okay thanks for all your work
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    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
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    (Original post by Mr M)
    Probably 3 marks and 1 mark respectively.
    Thank you very much!
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    (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
    As that question is worth 8 marks, I think you will lose 1 for failing to simplify.

    And you are welcome.
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    (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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