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    (Original post by Mr M)
    Q4) that's fine

    Q5) lose 1 mark

    I've provided a link to the correct graph on wolfram alpha a few pages ago.

    No idea about grade boundaries.
    Thank you! And for the last question if I had the correct method throughout but made arithmetic errors which were crazily stupid in getting me k=49 I should lose about 4? I expanded the brackets, then dy/dx=0 at x=-3 so subbed that and worked out k

    for the second part I got the answer of minimum because d2y/dx2 was greater than 0 it was 12 I think would I still get the marks despite wrong value for x?

    Finally for the last part, if I made gradient of curve=gradient of tangent so my dy/dx value equal to 9 and tried to factories how many marks would I lose? It was impossible with the values I had though

    sorry about the number of questions but really appreciate all the help

    thank you
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    (Original post by Mr M)
    Get one or two marks for finding P.
    Is that the same if I calculated the midpoint of PQ by mistake?


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    Hi Mr M
    For question 9 where we had to find K i got k to be -6 instead. How many marks do you think i would get...if i just added up wrong at the end.

    Also i did have root 81/4 but at the last minute i took off the root sign and put it to just 81/4 how many marks would i lose??

    For the completing the square question then finding the coordinates of minimum point if i completed the square wrongly....then would i get no marks for the miminum point part if i used what i got in the complete the square part???

    Thank you
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    For question 5)ii). I put y=2/(x^2)+5. Will I get 1 mark for this because of M1? Also for the radius of the circle, I put root40 instead of 2root10; will I still get the marks?
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    (Original post by gingerberry)
    Hello, for the last part of the last question, I did all of the correct working up until the last part where I got to the quadratic equation and factorised it but didn't put what x or y equaled (so no coordinate so I will lose the answer mark but will I get credit for the working up to that point?) but then I doubted myself and tried a different method afterwards which didn't come to an answer (as the method I did first was right) and I didn't cross out my first correct method but will I get penalised for then including a wrong method afterwards even though the second method didn't come to an answer either? Or will they just ignore my second wrong method and give me a few method marks for t hr first correct method or will I get 0 marks for that question?? Really worried as I need an A because this is a resit. Also, for the question where you had to find the length, I put "the square root of 81/4" but then afterwards instead of simplifying that down to just 9/2 I put "9/2 or -9/2" will I still get marks for that question or will the penalise me for including a wrong answer with my right answer and mark the whole question wrong??!*
    The second attempt will be marked.

    Drop one mark for -9/2.
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    (Original post by Z.M.1)
    Thank you! And for the last question if I had the correct method throughout but made arithmetic errors which were crazily stupid in getting me k=49 I should lose about 4? I expanded the brackets, then dy/dx=0 at x=-3 so subbed that and worked out k

    for the second part I got the answer of minimum because d2y/dx2 was greater than 0 it was 12 I think would I still get the marks despite wrong value for x?

    Finally for the last part, if I made gradient of curve=gradient of tangent so my dy/dx value equal to 9 and tried to factories how many marks would I lose? It was impossible with the values I had though

    sorry about the number of questions but really appreciate all the help

    thank you
    You might only lose 3 marks in total across question 10.
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    (Original post by ZachM)
    Is that the same if I calculated the midpoint of PQ by mistake?


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    I'm not really sure as that is such an odd thing to do.
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    (Original post by 4Hyunah)
    Hi Mr M
    For question 9 where we had to find K i got k to be -6 instead. How many marks do you think i would get...if i just added up wrong at the end.

    Also i did have root 81/4 but at the last minute i took off the root sign and put it to just 81/4 how many marks would i lose??

    For the completing the square question then finding the coordinates of minimum point if i completed the square wrongly....then would i get no marks for the miminum point part if i used what i got in the complete the square part???

    Thank you
    drop 1

    drop 1

    You will probably be able to get full marks on the minimum bit from using your wrong completed square bit.
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    (Original post by eddieko555)
    For question 5)ii). I put y=2/(x^2)+5. Will I get 1 mark for this because of M1? Also for the radius of the circle, I put root40 instead of 2root10; will I still get the marks?
    root 40 is fine - the other bit will probably get no credit.
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    HI,
    Please may I know what question 9 was
    thanks
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    Mr M? I did all the revision I can, i understood all the questions. How would you avoid silly mistakes? And how can I prepare for questions like the last question of Core1 yesterday? A question with an answer I have never seen before, with two values of x and got it wrong in the end. Where can I go to do really-difficult questions like those. If you were a student, How would you prepare for Core2 this Friday?
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    (Original post by ashraf549)
    Mr M? I did all the revision I can, i understood all the questions. How would you avoid silly mistakes? And how can I prepare for questions like the last question of Core1 yesterday? A question with an answer I have never seen before, with two values of x and got it wrong in the end. Where can I go to do really-difficult questions like those. If you were a student, How would you prepare for Core2 this Friday?
    Past papers all day long. The last question yesterday was similar to the last question in jan 2013..
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    (Original post by Mr M)
    Mr M's OCR (not OCR MEI) Core 1 Answers May 2013


    1. (i) 12 \sqrt 5 (2 marks)

    (ii) 4 \sqrt 5 (1 mark)

    (iii) 5 \sqrt 5 (1 mark)


    2. x=\frac{1}{2} or x=-1 (5 marks)


    3. (i) f'(x)=2-\frac{12}{x^3} (3 marks)

    (ii) f''(x)=\frac{36}{x^4} (2 marks)


    4. (i) 3(x+\frac{3}{2})^2+\frac{13}{4} (3 marks)

    (ii) (-\frac{3}{2}, \frac{13}{4}) (3 marks)

    (iii) -39 (2 marks)


    5. (i) Correct sketch (2 marks)

    (ii) y=\frac{2}{(x+5)^2} (2 marks)

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


    6. (i) Centre (0, -4) and radius 2 \sqrt{10} (3 marks)

    (ii) (-2, -10) (2 marks)


    7. (i) x<-\frac{1}{8} (2 marks)

    (ii) 0 \leq x \leq 5 (5 marks)


    8. 6x+2y-1=0 (7 marks)


    9. (i) Correct sketch with intersections at (-1.5, 0) and (2, 0) and (0, -6) (5 marks)

    (ii) x \leq \frac{1}{4} OR x < \frac{1}{4} (either will be marked correct) (3 marks)

    (iii) 4.5 (4 marks)


    10. (i) k=-5 (7 marks)

    (ii) Minimum (2 marks)

    (iii) (-2, -27) (5 marks)


    I'll be around to answer questions shortly.
    For question 2, I did all the right working out but my final answers were x=1/2 and x=-1/2 because I remembered, if you root anything, it should be plus or minus, and I stupidly didnt relize you could cube root a negative so I explicitly wrote, cant cube root -1!!! How much marks would I get for that question?
    Also for 5ii, I said a parallel stretch in the x axis by 0.5, would I still get a mark?
    For 6i, I wrote the radius as  \sqrt{40}, would I still get a mark? I got the right center.
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    if i wrote squash by 2 parallel to y, instead of stretch by 1/2....?
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    I know nobody knows the grade boundaries but would 71/72 get 100 UMS?
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    Can someone help me ? I Have the CASIO fx-991ES PLUS calculator and just wanted to check whether it was allowed in OCR Core 2 exams?
    Thanks
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    Mr M,
    For the completing the square question, I think in my working put I wrote down the question wrong as "3xsquared +9x - 10" instead of "3xsquared + 9x +10" so my working out for that question goes as follows:
    3xsquared +9x - 10
    3(xsquared +3x) - 10
    3(x + 3/2) -10 -(3 times 1.5squared)
    So my answer was "3(x +3/2)- 67/4" instead of "3(x+3/2) -13/4"
    Will I still get 2 marks out of 3 as I got the "3" and the "3/2" right, or will I get 0 marks for that question as every stage of working contains "-10" as I wrote it down wrong and therefore every working stage included this one wrong thing??
    And on the next question, that mean my y Co-Ordinate was wrong as I used the answer from the previous question, but I got the x Co-ordinate right, so how many marks out of 3 would I get for that question (1,2 or 0)????????
    Thankyou
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    what was the question for 5 ii please
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    Just 2 quick questions
    For 5(iii) I described the transformation of y = 1/x^2 to 2 / x^2 rather than the other way round. Will I lose 1 or 2 marks? I did put stretch parallel to the y-axis.

    And for 8 I left the equation of the line in y = mx + c form. How many marks will I lose for that?
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    For 5 (iii) would i drop a mark for not putting parallel, i put stretch scale factor of 1/2 in the y axis?:confused:
 
 
 
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