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

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    For 3ii, i accidently substituted a+b on the denominator instead of ab (even though i wrote ab) so got the answer as -1/k with the rest of the working correct. How many marks do you reckon ill lose? Thanks in advance
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    for the shear question is it okay to say a shear parallel to the x-axis by 3 units?
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    For the method of differences (q8) I forget to half the answer in ii), so carried this through to the next part of the question iii) - but I did write answers as a single fraction. Also for finding z (q2) I used -sqrt(3) - 3i instead of a positive sqrt(3) and also carried this onto the next part of the question. How many marks would I lose over these questions as a rough estimate? Thanks!
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    (Original post by beelal)
    For 3ii, i accidently substituted a+b on the denominator instead of ab (even though i wrote ab) so got the answer as -1/k with the rest of the working correct. How many marks do you reckon ill lose? Thanks in advance
    Probably only drop 1.
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    (Original post by HGT98)
    For the method of differences (q8) I forget to half the answer in ii), so carried this through to the next part of the question iii) - but I did write answers as a single fraction. Also for finding z (q2) I used -sqrt(3) - 3i instead of a positive sqrt(3) and also carried this onto the next part of the question. How many marks would I lose over these questions as a rough estimate? Thanks!
    Drop 1 mark in each case I expect.
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    (Original post by btsx)
    for the shear question is it okay to say a shear parallel to the x-axis by 3 units?
    Drop 1 mark.
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    (Original post by 0704)
    How many marks do you think I will lose if I put root 3 +3i for question 2i and therefore got an incorrect answer for part ii as I rationalised the wrong thing?
    Drop 1.
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    Q3i) i got wrote -1/k as -x/k and so for 3ii) got x^2/k^2
    Q2ii) misread the question and thought it was + 5i instead of - 5i
    will i get any marks on 2ii or 3ii?
    thanks for all the help
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    For 10(iii) do you get a mark for subbing in z=(1/u^2) and getting the equation given in the question?
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    What actually was question 8? I thought i'd managed to do it right but clearly not haha.
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    (Original post by 2807)
    For 10(iii) do you get a mark for subbing in z=(1/u^2) and getting the equation given in the question?
    Yes.
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    (Original post by lordkronos258)
    Q3i) i got wrote -1/k as -x/k and so for 3ii) got x^2/k^2
    Q2ii) misread the question and thought it was + 5i instead of - 5i
    will i get any marks on 2ii or 3ii?
    thanks for all the help
    Yes you'll probably lose 4 marks in total over the 2 questions.
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    Hi,

    How many marks do you think I'll lose if:
    For Q8ii & iii, I forgot to do the 1/2 and then the next part used the previous answer
    For Q10iii, I only got the 2 solutions rather than the 4.

    Also, for Q10ii, did you just have to sub in the root and then get 0 to get the mark?

    And how did you do Q6iii? I did it off sight and I think I got different answers to you.

    Thank you in advance!
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    I'm coming out with the answer (5n + 4) / (6n + 3). Can you explain how you derived the answer for 8iii
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    (Original post by Mr M)
    Mr M's OCR (not OCR MEI) Further Pure 1 Answers May 2016


    1. \displaystyle \frac{n(2n+3)(n-1)}{2} (5 marks)


    2. (i) \sqrt{3}-3i (2 marks)

    (ii) \displaystyle \frac{-1+4\sqrt{3} i}{49} (5 marks)


    3. (i) \displaystyle \alpha + \beta = -\frac{1}{k} and \displaystyle \alpha \beta = 1 (1 mark)

    (ii) \displaystyle \frac{1}{k^2} (5 marks)


    4. (i) \begin{pmatrix} 5a-3b & 10 & 0 \end{pmatrix} (2 marks)

    (ii) \begin{pmatrix} 6b-5 \end{pmatrix} (2 marks)

    (iii) \begin{pmatrix} 6a & 12 & 18 \\4a & 8 & 12 \\-a & -2 & -3 \end{pmatrix} (2 marks)


    5. Proof (4 marks)


    6. (i) \displaystyle |z-3-3i|=\sqrt 5 (4 marks)

    (ii) Sketch (2 marks)

    (iii) 2+5i and 4+i (3 marks)


    7. (i) Shear with x axis invariant taking the point (0, 1) to (3, 1) (2 marks)

    (ii) \begin{pmatrix} 0 & -1 \\-1 & 0 \\ \end{pmatrix}

    Reflection in the line y=-x (6 marks)


    8. (i) Show (1 mark)

    (ii) \displaystyle \frac{n}{3(2n+3)} (6 marks)

    (iii) \displaystyle \frac{1}{2(2n+1)} (3 marks)


    9. (i) Show (3 marks)

    (ii) Determinant = 0 when a = 3 so no unique solution. The equations are consistent because 3 x equation 3 - equation 1 = equation 2. (3 marks)


    10. (i) 5+4i and -5-4i (6 marks)

    (ii) Show (1 mark)

    (iii) \displaystyle \pm \frac{5}{41} \pm \frac{4i}{41} (4 marks)
    How many marks do you think you'd lose for having a 8ii of twice the correct answer (forgot to divide by 2 at the end) and then using that incorrect answer in 8iii (though my 8iii would have been correct had 8ii been correct)
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    (Original post by Nl1998)
    Hi,

    How many marks do you think I'll lose if:
    For Q8ii & iii, I forgot to do the 1/2 and then the next part used the previous answer
    For Q10iii, I only got the 2 solutions rather than the 4.

    Also, for Q10ii, did you just have to sub in the root and then get 0 to get the mark?

    And how did you do Q6iii? I did it off sight and I think I got different answers to you.

    Thank you in advance!
    8ii and iii. Drop 1 I expect.

    10iii. Drop 1.

    10ii. That's right.

    6iii. I cheated and used a computer.
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    (Original post by jjjjjjjjjjjj96)
    I'm coming out with the answer (5n + 4) / (6n + 3). Can you explain how you derived the answer for 8iii
    \displaystyle \sum_{r=n}^\infty = \sum_{r=1}^\infty - \sum_{r=1}^{n-1}
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    Would you be able to put question 8 on here because I would like to try it again?
    Also for 10 iii what did you do after subbing z=1/u^2 into the equation
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    (Original post by Mr M)
    \displaystyle \sum_{r=n}^\infty = \sum_{r=1}^\infty - \sum_{r=1}^{n-1}
    Please can you show how you got your answer?
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    what was the final result you had to get for the proof by induction??
 
 
 
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