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Math Help - Final Derivative concern..(some progress)

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    Final Derivative concern..(some progress)

    the derivative of :

     f(x) = \frac { 6 x^2 + 8 x + 5 } {\sqrt{x} },


    so far i get this using the quotient rule..but it's wrong:

     (12x+8)(x^(-1/2)) + (-1/(2sqrt(x)))(6x^2+8x+5)
    Last edited by frozenflames; October 9th 2009 at 07:03 PM.
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    here's where i am stuck after using the quotient rule..its showing as incorrect:

    [(12x+8x)(sqrt(x)) - [(-1/(2sqrt(x)))(6x^2+8x+5)]]/x

    or

     [(12x+8x)(sqrt(x)) - [(-1/(2sqrt(x)))(6x^2+8x+5)]]/x
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  3. #3
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    Quote Originally Posted by frozenflames View Post
    the derivative of :

     f(x) = \frac { 6 x^2 + 8 x + 5 } {\sqrt{x} },


    so far i get this using the quotient rule..but it's wrong:

     (12x+8)(x^(-1/2)) + (-1/(2sqrt(x)))(6x^2+8x+5)
    The quotient rule is the hard way and so can lead to mistakes that I'm not even going to bother trying to find.

    Break it up as  f(x) = 6 \frac{x^2}{\sqrt{x}} + 8 \frac{x}{\sqrt{x}} + \frac{5}{\sqrt{x}} = 6 x^{3/2} + 8 x^{1/2} + 5 x^{-1/2} and differentiate term-by-term.
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