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Math Help - differentiation

  1. #1
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    differentiation

    i have to differentiate this using the quotient rule...and i tried to do it but ended up with something that really, really does not look right...i'm wondering if anyone can help please? i know i know how to do this but i dont seem to be able to for some reason!
    thanks

    y = x/(9 + x squared)

    dy = ???
    dx
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  2. #2
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    Quote Originally Posted by Oranges&Lemons View Post
    i have to differentiate this using the quotient rule...and i tried to do it but ended up with something that really, really does not look right...i'm wondering if anyone can help please? i know i know how to do this but i dont seem to be able to for some reason!
    thanks

    y = x/(9 + x squared)

    dy = ???
    dx
    Hello,

    f(x)=\frac{x}{9+x^2} then using quotient rule

    f'(x) = \frac{(9+x^2)\cdot 1 - x \cdot 2x}{(9+x^2)^2}=\frac{9-x^2}{(9+x^2)^2}
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  3. #3
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    Quote Originally Posted by earboth View Post
    Hello,

    f(x)=\frac{x}{9+x^2} then using quotient rule

    f'(x) = \frac{(9+x^2)\cdot 1 - x \cdot 2x}{(9+x^2)^2}=\frac{9-x^2}{(9+x^2)^2}
    thankyou! i did actually get that...but then i tried to multiply it out for some odd reason..and got a really long answer! oops, my bad. its nice to know you got the same as me though. thanks again.
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