Help with solving a first order linear and first order non-linear

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 4K views
Xyius
Messages
501
Reaction score
4
Here is an image of the first order linear differential equation and my attempt to solve it. It ends in an integral that can not be solved.

http://img831.imageshack.us/img831/9937/math1.gif

And here is an image of the first order non-linear differential equation and my attempt to solve it. This one leads to a non-separable differential equation after a substitution.

http://img215.imageshack.us/img215/4893/math2.gif

Any advise?
 
Last edited by a moderator:
Physics news on Phys.org
You have:

[tex](1-y)dx+xydy=0[/tex]

You can find the [itex]1/M(M_y-N_x)[/itex] integrating factor for that.
 
jackmell said:
You have:

[tex](1-y)dx+xydy=0[/tex]

You can find the [itex]1/M(M_y-N_x)[/itex] integrating factor for that.

The integrating factor isn't working. I was under the impression you can only use the integrating factor only when the two partials differ by a constant only, which they do not. :\
 
Separable ODE :
 

Attachments

  • LambertW.JPG
    LambertW.JPG
    8.8 KB · Views: 482
y(x) cannot be expressed in terms of a finite number of elementary functions. The closed form requires a special function :
 

Attachments

  • ExpIntegral.JPG
    ExpIntegral.JPG
    9.8 KB · Views: 400