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Homework Help: Differentiation using the quotient rule

  1. Dec 5, 2012 #1
    1. The problem statement, all variables and given/known data

    Use the quotient rule to differentiate

    2. Relevant equations

    y=(v du/dx-u dv/dx)/v^2

    3. The attempt at a solution

    Please also find attached attempt as jpeg for clarity, and textbook supplied answer.

    dy/dx=([(4x-1).(8x^3-3)]-[〖(2x〗^4-3x).(4)])/((4x-1)^2 )

    dy/dx=([(4).(8×3x^(3-1) )]-[(2×4x^(4-1)-3).(4)])/((4x-1)^2 )

    dy/dx=((4).(24x^2 )-(8x^3-3).(4))/((4x-1)^2 )

    I think i can take out the two 4's in the numerator, apart from this i'm not entirely sure where i've gone wrong. If anyone has any advice to get me back on track that would be great. Thanks.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Dec 5, 2012 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    In your first attempt, you had a massive algebra mistake in the numerator of the derivative. The second attempt appears to be OK.
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