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Differential equations - finding solution

  1. Feb 13, 2010 #1
    Select the correct solution for dy/dx = 1/[(4y)*(x^3)]

    a) x^4
    b) x^(-1/4)
    c) 1/(x^4)
    d) x root 4

    Choice D means instead of cubic root, to the power 4 root

    Plz explain how to do this. I tried separating variables and integrating the choices but it didn't work. Mayb I should differentiate the solutions instead?

    Advice greatly appreciated
  2. jcsd
  3. Feb 13, 2010 #2


    Staff: Mentor

    You're making this harder than it needs to be. The problem isn't asking you to find the solution -- just say which of four given functions is a solution.

    For each of your four possible answers, take the derivative and see whether it is equal to 1/[(4 times the function)*x^3].
  4. Feb 13, 2010 #3


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    None of the answers are correct, so it is no wonder that when you solved it by separation of variables, nothing worked.
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