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Math Help - Can't find derivative

  1. #1
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    Can't find derivative

    I can't find the derivative of:

    f(x) = (2x^2) / (x^2-1)

    Having a hard time with this one.
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  2. #2
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    Quote Originally Posted by thekrown View Post
    I can't find the derivative of:

    f(x) = (2x^2) / (x^2-1)

    Having a hard time with this one.

    First way: quotient rule: f'(x)=\frac{4x(x^2-1)-2x(2x^2)}{(x^2-1)^2}=\frac{-4x}{(x^2-1)^2}

    Second way: first write f(x)=2+\frac{2}{x^2-1} and now we only need the derivative of \frac{1}{x^2} :

    f'(x)=\frac{-4x}{(x^2-1)^2}

    Tonio
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  3. #3
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    Quotient rule! Oh yes I remember this and had forgotten it just as quickly. Yes I believe it is uv'-vu' / 2v or something... I will look into this and try this again. Thanks.
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