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Math Help - straight line

  1. #1
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    straight line

    Figure shows a straight line graph of log10y against log10x.


    Given y=x^2n/k where n and k are constants.Calculate the value of n and k.
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  2. #2
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    Quote Originally Posted by mastermin346 View Post
    Figure shows a straight line graph of log10y against log10x.


    Given y=x^2n/k where n and k are constants.Calculate the value of n and k.
    hi

    y=\frac{x^{2n}}{k}

    \lg y=\lg {\frac{x^{2n}}{k}}

    \lg y=2n\lg x-\lg k

    from the graph , we can see that the gradient is 1/2

    so 2n=1/2 , n=1/4

    - lg k =-1

    lg k=1

    k=??
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  3. #3
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    Quote Originally Posted by mathaddict View Post
    hi

    y=\frac{x^{2n}}{k}

    \lg y=\lg {\frac{x^{2n}}{k}}

    \lg y=2n\lg x-\lg k

    from the graph , we can see that the gradient is 1/2

    so 2n=1/2 , n=1/4

    - lg k =-1

    lg k=1

    k=??
    how u get -logk=-1??
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  4. #4
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    Quote Originally Posted by mastermin346 View Post
    how u get -logk=-1??
    -log k is the y-intercept
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  5. #5
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    Quote Originally Posted by mastermin346 View Post
    how u get -logk=-1??

    owh..at point (o,-1), thanks a lot
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