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Math Help - derivative help

  1. #1
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    derivative help

    a little confused on this derivative, my professor posted the answers and he has this answer as \frac{-19}{112} but i'm not seeing how he's getting that. any help is really appreciated.

    find the derivative and f\prime(2)

    f(x) = \frac{x^3+2x+3}{x^4+3x+6}<br />


    if i use product rule i get


    <br /> <br /> <br />
f\prime(x) = \frac{(3x^2+2)(x^4+3x+6) - (x^3+2x+3)(4x^3+3)}{(x^4+3x+6)^2}

    i've done it two different ways and come up with \frac{-35}{784} or \frac{-133}{784}


    please help, final is tomorrow !
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  2. #2
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    derivative

    Hello,

    Your derivative is correct and f'(2)=\frac{-133}{784}
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  3. #3
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    that's what i figured, he posted a couple answers that seemed a bit off so i assume he made mistakes. he's just giving me anxiety about how i'm solving these problems hahaha. thanks again
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