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Math Help - derivative problem

  1. #1
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    derivative problem

    Given f(x) = (x^3-2x)/sqrt(2x+1) find f'(x)

    I can do the first step but then I'm stuck.. Can't wait to fail my test friday.
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  2. #2
    MHF Contributor Drexel28's Avatar
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    Quote Originally Posted by tbenne3 View Post
    Given f(x) = (x^3-2x)/sqrt(2x+1) find f'(x)

    I can do the first step but then I'm stuck.. Can't wait to fail my test friday.
    Is this a multi-stepped problem?
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  3. #3
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    Quote Originally Posted by Drexel28 View Post
    Is this a multi-stepped problem?
    Don't know.. If I give you the answer could you figure it out?
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    Just use the quotient rule, taking the chain rule into consideration. Are you still stuck after that? I'm not sure what 'step' you're on in your solution. ^^
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  5. #5
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    Quote Originally Posted by experiment00005 View Post
    Just use the quotient rule, taking the chain rule into consideration. Are you still stuck after that? I'm not sure what 'step' you're on in your solution. ^^
    Hmm.. I thought all I would need to do is the quotient rule.. Why does the chain rule need to be applied to?
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  6. #6
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    The square root: \sqrt{f(x)}= (f(x))^{1/2} so, by the chain rule, its derivative is (1/2)(f(x))^{-1/2}f'(x).
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  7. #7
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    Quote Originally Posted by tbenne3 View Post
    Given f(x) = (x^3-2x)/sqrt(2x+1) find f'(x)

    I can do the first step but then I'm stuck.. Can't wait to fail my test friday.
    Asked again here: http://www.mathhelpforum.com/math-he...erivative.html

    Thread closed.
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