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Honors Maths Question Help...

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  • 07-04-2007 2:57pm
    #1
    Citizen_Erased
    Closed Accounts Posts: 1,254 ✭✭✭Citizen_Erased


    Hi all,
    Just been getting down to some study and I have come across this question which had me slightly stumped so I went onto the e-xamit site to have a look at their solution.
    The Question is LC 2005 , Paper 1 , Question 6, C (iii). You are being asked to prove that the curve is its own image under central symmetry through the point of intersection of the asymptotes .Here is the solution from e-xamit.ie (btw code is cbmoqg if you wanna check it for yourself) and it is fairly comprehensible until the bit I have highlighted in red. Surely I am not mistaking in saying that what it says there is completely incorrect? Any suggestions at all?
    20056ciiikv9.jpg
    Thanks
    C_E


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    #2
    Willow Important Rattan
    Posts: 0 ✭✭✭✭ Willow Important Rattan


    no, its correct. they convert the 2 into 2(a-1/a-1). i.e (2a-2)/a-1.

    This puts 2a-2-a above the line (a-1 below) which becomes a-2/a-1


    make sense?


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    #3
    Citizen_Erased
    Closed Accounts Posts: 1,254 ✭✭✭Citizen_Erased


    Yes I have it at a-2/a-1 , what I dont get is how it then jumps it to 2-a/a-1 .


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    #4
    Willow Important Rattan
    Posts: 0 ✭✭✭✭ Willow Important Rattan


    ok

    2 - a/(a-1)

    becomes

    2*(1) - a/(a-1)

    becomes 2*(a-1)/(a-1) - a/(a-1)

    becomes (2a-2)/(a-1) - a/(a-1)

    = (2a-2-a)/(a-1)

    = (a-2)/(a-1)

    clearer?


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    #5
    Willow Important Rattan
    Posts: 0 ✭✭✭✭ Willow Important Rattan


    oops, yeah that's wrong...


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    #6
    Citizen_Erased
    Closed Accounts Posts: 1,254 ✭✭✭Citizen_Erased


    Sorry I am not being very clear here , I have that bit that you have described that is not my problem , hang on a minute I will post image to clarify.
    Heres the image ...
    qhmbj3.jpg

    {edit} Yep , Emmet theres defo something up with it , sorry I wasn't clearer earlier but it's great to here it from someone else now too. Thanks for the help.


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    #7
    Willow Important Rattan
    Posts: 0 ✭✭✭✭ Willow Important Rattan


    no i see it know, it should have become 2-a/1-a if they were going to multiply it by -1/-1


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    #8
    Citizen_Erased
    Closed Accounts Posts: 1,254 ✭✭✭Citizen_Erased


    Actually I think I have it now , it is just a typing error or whatever because later on in the question it is refared to as 2-a/1-a so they did just multiply by -1/-1 but just a typo or whatever in that line and the next is the problem.
    So problem solved , thanks for your help Emmet.

    C_E


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