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Homework Help: Find integrating factor and solve the equation 2

  1. Mar 27, 2010 #1
    Question:

    (1 - x - z)dx + dz = 0

    let M = (1 - x - z) ; N = 1

    dM/dz = -x ; dN/dx = 0
    hence, not exact.

    integrating factor...

    1/N[ dM/dz - dN/dx ] = 1[-x]
    .................................= -x

    e^∫-x dx = e ^ [(-x^2)/2]


    times integrating factor with DE..

    {e ^ [(-x^2)/2] -x e ^ [(-x^2)/2] - z e ^ [(-x^2)/2]}dx +
    e ^ [(-x^2)/2]dz = 0

    dM/dz = -e ^ [(-x^2)/2] ; dN/dx = -xe ^ [(-x^2)/2]

    the problem is, i calculated the integrating factor.. but, the equations still not the exact calculation.
     
  2. jcsd
  3. Mar 27, 2010 #2

    gabbagabbahey

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    Homework Helper
    Gold Member

    Did you forget how to differentiate?:wink:
     
  4. Mar 27, 2010 #3
    oh s#|t..!!
    it should be -1
    thanks gabbagabbahey
     
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