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C1 help!

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    Just did a Paper E of the soloman papers and the mark scheme seems to be corrupt If anyone has the markscheme could they post it here? and if you don't could you help me with the questions?

    So there are a few questions which I really couldn't do



    For this I could not do part C, I got (0, -1) which is defin wrong, I got this by equating the two equations




    This is for part B, I differentiated from the earlier equation and got

    (3/4) x ^(1/2) -2x^(-1/2) -4x^ (-3/2)

    But not sure how I would rearrange this to get it in the form that they want




    Lastly need help with part b, I got the gradient as 10 but couldn't get to the equation they wanted I got y = 10x - 2

    For the contact part I got dy/dx and made it equal to 10, I then solved and got
    x = 1
    or
    x= -7/3

    Corresponding y values I got were 0 and -229/27



    Thanks guys
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    8. C)

    When you equate the two equations you should end up with 2x^2 - 2x - 1. Use the quadratic formula to factorise this and get it in the form a + b\sqrt3

    7. B) Highly doubt that would come up in a C1 exam paper as half the candidates wouldn't be able to answer it

    10. B) It says to show the line y = x - 2 is a tangent to C

    What's C? C is the equation of the line which you should have got in part a) when you integrated the dy/dx and found k
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    (Original post by isp)
    8. C)

    When you equate the two equations you should end up with 2x^2 - 2x - 1. Use the quadratic formula to factorise this and get it in the form a + b\sqrt3

    7. B) Highly doubt that would come up in a C1 exam paper as half the candidates wouldn't be able to answer it

    10. B) It says to show the line y = x - 2 is a tangent to C

    What's C? C is the equation of the line which you should have got in part a) when you integrated the dy/dx and found k

    Urmm C is x^3 +2x^2 +2x -2


    How did you get 2x^2 - 2x - 1 ?
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    (Original post by 0range)
    Urmm C is x^3 +2x^2 +2x -2


    How did you get 2x^2 - 2x - 1 ?
    Alright I wrote it on paper as I cannot be bothered with latex.

    Spoiler:
    Show


    For question 10)

    Yes for C that is correct it is x^3 + 2x^2 + 2x - 2

    Now equal both of them together and you get x^3 + 2x^2 + 2x - 2 = x - 2

    x^3 + 2x^2 + x = 0

    Now factorise this

    hint:
    Spoiler:
    Show
    take out a factor of x
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    (Original post by isp)
    Alright I wrote it on paper as I cannot be bothered with latex.

    Spoiler:
    Show


    For question 10)

    Yes for C that is correct it is x^3 + 2x^2 + 2x - 2

    Now equal both of them together and you get x^3 + 2x^2 + 2x - 2 = x - 2

    x^3 + 2x^2 + x = 0

    Now factorise this

    hint:
    Spoiler:
    Show
    take out a factor of x
    Ahh yup that's wicked, Thank you!!!
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    For question 7b youi can just use the quotient rule

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Updated: May 14, 2012
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