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Homework Help: Bernoulli Differential Equation?

  1. Mar 2, 2010 #1
    I keep getting stuck on one part of the equation. can somebody help?

    dy/dx = y(xy3 - 1)

    dy/dx = xy4 - y

    dy/dx + y = xy4

    u = y1-n = y-3

    y = u-3

    dy/dx = dy/du * du/dx

    dy/dx = -3u-4 du/dx

    Substituting terms into the original equation

    -3u-4 du/dx + u-3 = x(u-3)4

    Here is where I get stuck. When I divide u-4 to clean up the equation, the right hand side still has u-8 remaining. I will not be able to go on since the right hand side can only have x terms. What am I doing wrong?
    Last edited: Mar 2, 2010
  2. jcsd
  3. Mar 2, 2010 #2


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    Science Advisor
    Homework Helper

    Hi jofree87! :smile:
    erm :redface: … noooo! :wink:
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