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Thread: surds question

  1. #1
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    surds question

    Q:
    Given, when simplified the expression
     (2x)^{-1}\times \frac{3}{\sqrt{x}}\times (6x^{n})^{2}
    independent of terms in x:
    (a) Find the value of n
    (b) Write down the value of the expression

    My attempt:
    part (a)  =(2x)^{-1}\times \frac{3}{\sqrt{x}}\times (6x^{n})^{2}
    =\frac{1}{2x}\times 3x^{-\frac{1}{2}}\times 36x^{2n}
     = 54 x^{2n-\frac{3}{2}}
     2n-\frac{3}{2} = 0

    n = \frac{3}{4}

    b) using part a

     = 54 x^{2n-\frac{3}{2}}
    sub n into the expression
     = 54 x^{(2(\frac{3}{4})-\frac{3}{2})}
     = 54

    Please can someone check i don't know if I am right.

    Thank you
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  2. #2
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    Re: surds question

    Yes that's correct. Well done!
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  3. #3
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    Re: surds question

    Quote Originally Posted by bigmansouf View Post
    (a) Find the value of n
    (b) Write down the value of the expression
    Find the value of n *what*?

    There is no specified problem for (a). It could be
    "Find the value of n which makes the exponent equal to zero."
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  4. #4
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    Re: surds question

    Quote Originally Posted by greg1313 View Post
    Find the value of n *what*?

    There is no specified problem for (a). It could be
    "Find the value of n which makes the exponent equal to zero."
    Greg1313, You seemed to have missed the bit in red:

    Given, when simplified the expression
    (2x)^{-1}\times \frac{3}{\sqrt{x}}\times (6x^{n})^{2}
    independent of terms in x:
    (a) Find the value of n
    (b) Write down the value of the expression
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  5. #5
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    Re: surds question

    thank you
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