Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Differential- integral factor by inspection

  1. Oct 21, 2011 #1
    i'm trying to solve the problem by finding the integral factor by inspection:

    1) y(2 - 3xy)dx - xdy =0
    2) y(x^2+y^2-1)dx + x(x^2+y^2+1)dy=0

    i can't solve those two questions! Help please.

    Thanks in advance
  2. jcsd
  3. Oct 21, 2011 #2


    User Avatar
    Homework Helper

    What have you tried? When guessing integrating factors it helps to factor and keep in mind common examples such as
    d(xy)=x dy+y dx
    y2 d(x/y)=y dx-x dy
    x2 d(y/x)=x dy-y dx
    (x2+y2) d(arctan(y/x))=x dy-y dx
    [tex] x^{1-p}y^{1-q}{d}(x^py^q)=pydx+qxdy[/tex]
    and so on
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook