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Math Help - Rate of Change

  1. #1
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    Lightbulb Rate of Change

    Got stuck on this one: Thanks!

    Let f(x)=x(1-2x)
    a. Find the average rate of change of f(x) with respect to x as x changes from x=0 to x=1/2
    b.Find the instantaneous rate of change of f(x) at x =0
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  2. #2
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    Quote Originally Posted by lisa1984wilson View Post
    Got stuck on this one: Thanks!

    Let f(x)=x(1-2x)
    a. Find the average rate of change of f(x) with respect to x as x changes from x=0 to x=1/2
    b.Find the instantaneous rate of change of f(x) at x =0
    a. \frac{f\left(\frac{1}{2}\right) - f(0)}{\frac{1}{2} - 0}

    b. \lim_{x \to 0} \frac{f(x) - f(0)}{x - 0}

    where, exactly, are you "stuck" ?
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  3. #3
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    I can get the first part but I'm not very good with the lim part don't know how to calculate it without a calculator!
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  4. #4
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    Show us what you've done so far. The limit is very easy to figure out, so you should under no circumstances be using a calculator for it.
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  5. #5
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    lim=f(x)-f(0)/x-0
    lim= √x-0/x-0
    lim=
    √x-0/ (√x-0)( √x+0
    lim=0/
    √+1
    lim=0/1=0
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  6. #6
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    f(x)=x(1-2x), so why are you using f(x)=\sqrt{x}?
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