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Elementary Differential Equations

  1. Jan 25, 2012 #1
    (dy/dx)^2 + y^2 + 4 = 0; Show that there are no real valued solutions.

    (dy/dx)^2 = -(y^2 + 4)
    dy/dx= sqrt( -(y^2 + 4)) -----> This is the answer I got, I feel it makes sense because the negative under the radical produce an answer with 'i' or an imaginary sol'n and since y^2 is always positive y^2 + 4> 0, so the there is no way to cancel that negative under the radical.
    Unfortunately, this doesn't correspond with the answer in the back of my book, anyone want to let me know what I am doing wrong/ show me a different way to answer it? Thanks.
  2. jcsd
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