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Math Help - What Is Derivative of (f(x))?

  1. #1
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    What Is Derivative of (f(x))?

    What Is Derivative of (f(x))? I am confused with that square sign thrown in there.
    Last edited by mr fantastic; October 21st 2009 at 07:29 PM. Reason: Added post title to main body of post.
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  2. #2
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    Quote Originally Posted by r2d2 View Post
    I am confused with that square sign thrown in there.
    \frac{d}{dx}f^2(x) = \frac{d}{dx}(f(x)\cdot f(x)) = f(x)\cdot \frac{d}{dx}(f(x)) + \frac{d}{dx}(f(x))\cdot f(x) = 2f(x)f'(x)
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  3. #3
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    So then would the second derivative be:

    d/dx f'(x)(f(x)*2= [2 d/dx f''(x)f(x) +f'(x)f'(x)] = 2f''(x)f(x) + 2f'(x)f'(x)

    would that be right, pulling the 2 out in front?
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  4. #4
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    Quote Originally Posted by r2d2 View Post
    So then would the second derivative be:

    d/dx f'(x)(f(x)*2= [2 d/dx f''(x)f(x) +f'(x)f'(x)] = 2f''(x)f(x) + 2f'(x)f'(x)

    would that be right, pulling the 2 out in front?
    Yes, that is correct.
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  5. #5
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    Great, Just want to make sure. Thanks again, defunkt
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