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Solve 2x + y + y' x = 3y^2 y', why is this wrong?

  1. Jun 17, 2008 #1
    2x+y+(dy/dx)x=3y^2(dy/dx)
    This is wrong:
    (dy/dx)(x-3y^2)=-2x-y
    This is right:
    2x+y=(3y^2-x)(dy/dx)

    Can someone please explain why.
     
  2. jcsd
  3. Jun 17, 2008 #2

    Those two equalities are actually the same, so I'm not sure "right" and "wrong" really apply.
    The only difference is that the second is the negative of the first.
    If you move each side of the first equality over the equals sign you will get the second
     
  4. Jun 17, 2008 #3

    Defennder

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    Yeah, scottie_000 is right. Multiply the first by -1 and you'll get the second.
     
  5. Jun 18, 2008 #4
    So either answer would be correct in an exam?
     
  6. Jun 18, 2008 #5

    Defennder

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    Of course, if they were strictly equivalent and your teachers don't mind.
     
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