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Homework Help: Use the chain rule to find the derivative

  1. Feb 12, 2010 #1
    1. The problem statement, all variables and given/known data
    f(x) = ((x^2+2)^2)/(x+2)^1/2
    Use the chain rule to find the derivative

    2. Relevant equations
    None


    3. The attempt at a solution
    ((x^2+2)^2)(x+2)^-1/2

    PS: Answer in the book is 3x((x^2+2)^1/2)

    I have no idea how they get it there, would like some help, thx!
     
  2. jcsd
  3. Feb 12, 2010 #2

    Mark44

    Staff: Mentor

    Re: Derivative

    It looks like you completely missed the fact that this is a quotient (use the quotient rule first). As part of using the quotient rule, you'll need the chain rule.
     
  4. Feb 12, 2010 #3
    Re: Derivative

    ohh thx! I will try it again (reserved)
     
  5. Feb 13, 2010 #4

    Mark44

    Staff: Mentor

    Re: Derivative

    BTW, questions on derivatives really should go in the Calculus & Beyond section, not the Precalc section.
     
  6. Feb 14, 2010 #5

    HallsofIvy

    User Avatar
    Science Advisor

    Re: Derivative

    Or, since the product rule is (to me anyway) less complicated than the quotient rule, write your function as [itex]f(x) = (x^2+2)^2(x+2)^{-1/2}[/itex] and use the product rule, together with the chain rule.
     
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