1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Differential equations

  1. Oct 23, 2009 #1
    i just started a course in differential equations, and this question was in the homework that i got, im not sure we learned how to solve it but maybe i am meant to know.

    xy' + y = sqrt(x-1)

    up until now all i have been able to solve is equations which i can bring to a form of dx/x +dy/y = 0 or something like that

    because this question has 3 parts i havent been able to get F(x)dx + F(y)dy=0

    xy' + y = sqrt(x-1)

    x*dy/dx + y =sqrt(x-1)

    dy/y + x*dx = sqrt(x-1)*dx/y

    dy/y = (sqrt(x-1)/y - x )dx

    now i cant integrat this because on the right i have y as well as x and cannot get rid of it
  2. jcsd
  3. Oct 23, 2009 #2
    Looks like you are familiar only with separable differential equations. Have you learned about integrating factors? That's what you need to solve this DE.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook