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Edexcel C3 June 2016 - Unofficial Mark Scheme watch

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    What was the thing you had to differentiate in Q2??
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    (Original post by Narxs)
    I did 4e^2x =25
    e^2x=25/4
    2x=ln(25/4)
    x=0.5ln(25/4)

    But didn't simplify ant further would this be alright??
    You might lose 1 mark, I think it said it wanted answers in their simplest form. It is equivalent though.
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    I got 1/2ln(6.25) which is the same as ln(2.5)
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    Does anyone know mark by mark what each question was worth?
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    What is the answer of question 1A, mine is 1/6
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    Does anyone know what the functions were for question 1 since I somehow got it wrong.
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    (Original post by sierra117)
    I believe you're wrong. It was -4x^2 + 20, not -20. Therefore the answer stated by this post is correct.
    Hmm I think i did something stupid in the exam saying that -4x^2+20 = -4(x^2+5) which is wrong. Would I get the final mark for writing the -4x^2+20/(x^2+5)^2 ? Because I definitely wrote that.
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    totally correct. i even remember checking them on my calculator
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    How many marks q6 was
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    (Original post by cookie_raider01)
    I got 1/2ln(6.25) which is the same as ln(2.5)
    It asked for simplest form; you could root that (as it's half a log) and get ln2.5.
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    Can someone tell me the equations for question 1

    I cant ****ing believe I couldn't solve it.

    You put G into F then you equate it to X?

    why was I getting a unsolvable quadratic equation

    **** my life
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    (Original post by eyeman567)
    Can someone tell me the equations for question 1

    I cant ****ing believe I couldn't solve it.

    You put G into F then you equate it to X?

    why was I getting a unsolvable quadratic equation

    **** my life
    fg(x) = x
    g(x) = f^-1(x)

    Find the inverse of then equate and solve.
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    (Original post by Mattematics)
    fg(x) = x
    g(x) = f^-1(x)

    Find the inverse of then equate and solve.
    What were the equations for F and G
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    (Original post by eyeman567)
    What were the equations for F and G
    I can't remember, sorry.
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    (Original post by eyeman567)
    What were the equations for F and G
    I would like to know this. Am sure I have got 72/75 except if I didn't get question 1 correct - which I cant remember if i got 5 and -6
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    (Original post by veldt127)
    I'm not 100% sure on all of these, but I think most are correct.

    1.
    A -5, 6
    B 6

    2.
    A (20-4x^2)/(x^2+5)^2 Might not be simplest form
    B >sqrt(5), <-sqrt(5)

    3.
    A R= sqrt(5)
    a= 26.57°
    B 33.0°, 273.9°
    C 86.1°

    4.
    Ai 21
    ii ln(2.5)
    iii 25
    B Show that question
    C 1.4368, 1.4373
    D Show the root was in [1.4365, 1.4375]

    5.
    i 0.9463
    ii 0.5cosec(4Y)

    6.
    A A=3, B=4
    B Normal eqn. -0.5x + 17.5

    7.
    A graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
    B -1-0.5sqrt(3)

    8.
    A Trig proof
    B -2.848, -1.277, 0.294, 1.865

    9.
    A 6.740 - dose after 4 hours
    B show that dose equalled a value after 7 hours
    C 5ln(2 + 2e^-1)
    A = 5, B = 2

    Sorry about the formatting, I'll try to improve it once I'm home.
    do you have the mark allocations?
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    F********K.

    Omg for 3.a. I got r=root(5) , and I got a=63.43...

    I got the value of 'a' wrong and I used this value for the rest of my question!!!!!
    How many marks would I lose if I got the method correct?
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    (Original post by Dieselblue)
    For 5i what did people do with the sin and cos?

    Also part 2a is wrong, -4x^2-20=-4(x^2+5) so -4/x^2+5
    nope it was 20-4x^2. not -20-4x^2. there was no further cancellation
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    Agree with all
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    Working for 8a and 7
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