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    • Thread Starter
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    http://www.examsolutions.net/a-level...y/paper.php#Q7

    7b

    why isn't this right?
    let
    x=\dfrac{1}{2y-1}

    x(2y-1)=1

    2y-1=\frac{1}{x}

    2y=\frac{1}{x}+1

    y=\dfrac{\frac{1}{x} +1}{2}
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    The last step you took was halve both sides, right? If we take the half out, so we're left with 0.5(1/x+1), we can then expand out properly to get y=1/2x+1/2=(1+x)/2x
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    (Original post by an_atheist)
    The last step you took was halve both sides, right? If we take the half out, so we're left with 0.5(1/x+1), we can then expand out properly to get y=1/2x+1/2=(1+x)/2x
    oh ok i see
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    You are correct.
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    (Original post by bigdonger)
    why isn't this right?

    Why do you think it's not right?
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    (Original post by B_9710)
    You are correct.
    ah...
    (Original post by Zacken)
    Why do you think it's not right?
    because it wasn't the same as the "most simplified" version of the answer which was in the solution video.
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    (Original post by bigdonger)
    Because it wasn't the same as the "most simplified" version of the answer which was in the solution video.
    Alright, can you see how to simplify it down now?
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    (Original post by Zacken)
    Alright, can you see how to simplify it down now?
    yes
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    (Original post by bigdonger)
    yes
    Great.
 
 
 
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