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    Mr M's OCR (not OCR MEI) Core 1 Answers May 2015


    1. 4\sqrt3+4 (3 marks)


    2. (i) Curve in second and fourth quadrants (2 marks)

    (ii) y=\frac{1}{2-x} (2 marks)

    (iii) Stretch parallel to y axis (or x axis) scale factor \frac{1}{3} (2 marks)


    3. (i) 5^8 (1 mark)

    (ii) 5^{-\frac{1}{4}} (2 marks)

    (iii) 5^{\frac{9}{2}} (2 marks)


    4. x=27 or x=-8 (5 marks)


    5. (i) 5 (2 marks)

    (ii) 6x-8y-29=0 (7 marks)


    6. x=2 and y=1 or x=\frac{14}{3} and y=-\frac{13}{3} (5 marks)


    7. (a) -3x^2+10x-3 (4 marks)

    (b) -\frac{1}{48} (4 marks)


    8. (i) U shaped parabola passing through (-1, 0), (0, -3) and (\frac{3}{2}, 0) (4 marks)

    (ii) x<-1 or x>\frac{3}{2} (2 marks)

    (iii) k<-\frac{25}{8} (3 marks)


    9. (i) a=13 (5 marks)

    (ii) Minimum (2 marks)

    (iii) x=\frac{1}{3} (3 marks)


    10. (i) Centre (5, -2) and radius 5 (3 marks)

    (ii) Show ... (5 marks)

    (iii) 40 square units (4 marks)
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    for 8iii) i wrote b^2 - 4ac< 0 , then worked it out but put k >25 instead of the other way round k<-25.

    How many marks do you expect me to get from that?
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    (Original post by ccfctom)
    for 8iii) i wrote b^2 - 4ac< 0 , then worked it out but put k >25 instead of the other way round k<-25.

    How many marks do you expect me to get from that?
    1 mark for using the discriminant.
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    thanks for this! ^^

    edit: any chance you're doing OCR FP1?
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    Isn't 2ii incorrect?
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    I left 2ii) as -1/(x-2) do you think I'll lose a mark for this?
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    Ahh okay I'm sure I achieved 60-63 hmm, I wonder what the boundary for an A will be! What do you believe in your opinion? (And thankyou!)
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    (Original post by AlfieH)
    Isn't 2ii incorrect?
    over (x-2) is it?
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    (Original post by jackpethick)
    over (x-2) is it?
    The original curve was -1/x therefore if it was a translation +2 units in the x direction the new equation would be -1/x-2?
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    (Original post by higgin97)
    I left 2ii) as -1/(x-2) do you think I'll lose a mark for this?
    No.
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    (Original post by AlfieH)
    Isn't 2ii incorrect?
    No.

    You have probably written y=-\frac{1}{x-2}. This is exactly the same.
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    (Original post by AlfieH)
    The original curve was -1/x therefore if it was a translation +2 units in the x direction the new equation would be -1/x-2?
    That's the same as the answer. Multiply numerator and denominator by -1.
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    (Original post by nobodycarescarla)
    Ahh okay I'm sure I achieved 60-63 hmm, I wonder what the boundary for an A will be! What do you believe in your opinion? (And thankyou!)
    I've no idea and I don't like to guess. We'll just have to wait and see.
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    (Original post by Mr M)
    No.

    You have probably written y=-\frac{1}{x-2}. This is exactly the same.
    Ahh that makes sense, it's hard to remember what exactly i got. Cheers.
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    (Original post by Parallex)
    thanks for this! ^^

    edit: any chance you're doing OCR FP1?
    Tomorrow evening I will.
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    (Original post by Mr M)
    No.
    Hi, are you doing any answers for the AQA C1 maths? Would be reeeeaaallly appreciated if so )
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    (Original post by Golem.)
    Hi, are you doing any answers for the AQA C1 maths? Would be reeeeaaallly appreciated if so )
    I only do OCR for A Level. Sorry.
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    (Original post by Mr M)
    That's the same as the answer. Multiply numerator and denominator by -1.
    I was misled then by google graphs since entering y=1/ 2-x gives a straight line graph.

    Name:  Screen Shot 2015-05-14 at 18.54.53.png
Views: 945
Size:  53.8 KB

    EDIT: Forgot the brackets! Sorry for being a goon. Cheers!
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    (Original post by Mr M)
    Tomorrow evening I will.
    Thanks.
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    Is there any chance you could post the c1 paper?
 
 
 
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