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Math Help - [SOLVED] Find first and second derivative.

  1. #1
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    [SOLVED] Find first and second derivative.

      f(x) = 2x^2+\frac{8}{x^2}

    f'(x) = 4x +16x^{-1} => 4x+\frac{16}{x}

    f''(x) = 4 -16


    Is that right?
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  2. #2
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    Hi el123!

    Quote Originally Posted by el123 View Post
      f(x) = 2x^2+\frac{8}{x^2}

    f'(x) = 4x +16x^{-1} => 4x+\frac{16}{x}
    No, that is not correct. You tried to integrate or something.

    If
    g(x) := 8*\frac{1}{x^2} = 8*x^{-2}

    then

    g'(x) = -2*8*x^{-2-1} =-2*8*x^{-3} = -16*\frac{1}{x^3}

    Thus f'(x) = 4x -16*\frac{1}{x^3}

    Do you think you find the second derivative on your own?

    Yours
    Rapha
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  3. #3
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    is it  f''(x) = 4 +48x^{-4}?
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  4. #4
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    Hello.

    Quote Originally Posted by el123 View Post
    is it  f''(x) = 4 +48x^{-4}?
    That is correct.

     f''(x) = 4 +48x^{-4} = 4 + \frac{48}{x^4}

    Rapha
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  5. #5
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    Cheers mate.
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