How Can This Non-Separable First Order ODE Be Solved?

  • Thread starter Thread starter mmh37
  • Start date Start date
  • Tags Tags
    First order Ode
Click For Summary
SUMMARY

The discussion centers on solving the non-separable first-order ordinary differential equation (ODE) given by the expression [2y*exp^{y/x} + x] dy/dx - 2x - 2y = 0. The user attempts to rearrange the equation to isolate dy/dx, resulting in dy/dx = (2x + 2y) / (2y*exp^{y/x} - x). Despite this effort, the user struggles to find an integrating factor or further progress. A suggested approach involves a change of variable, u = y/x, which leads to the expression du/dx = (1/x) dy/dx - y/x² = (1/x) dy/dx - u/x.

PREREQUISITES
  • Understanding of first-order ordinary differential equations (ODEs)
  • Familiarity with the concept of integrating factors
  • Knowledge of variable substitution techniques in differential equations
  • Proficiency in exponential functions and their properties
NEXT STEPS
  • Research methods for solving non-separable first-order ODEs
  • Learn about integrating factors and their application in differential equations
  • Study variable substitution techniques, specifically for ODEs
  • Explore the properties and applications of exponential functions in differential equations
USEFUL FOR

Mathematics students, educators, and professionals working with differential equations, particularly those dealing with non-separable first-order ODEs.

mmh37
Messages
56
Reaction score
0
Does anyone see how one can tackle the following ODE?

[tex][2y*exp^{y/x} + x}] \frac {dy} {dx} -2x - 2y = 0[/tex]

that is my attempt:

rearrange to get

[tex]dy/dx = \frac {2x + 2y} {2y*exp^{y/x}-x}[/tex]

I do not see how to go on from here. Surely, the ODE is not seperabale and I don't find a way to get the integrating factor here.

thanks for any hints!

[edit:] for a more clearly written version of the ODE see attached file
 

Attachments

  • Zwischenablage01.jpg
    Zwischenablage01.jpg
    2.2 KB · Views: 537
Last edited:
Physics news on Phys.org
First thought would be to try a change of variable, u = y/x, so

du/dx = (1/x) dy/dx - y/x2 = (1/x) dy/dx - u/x
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
19
Views
3K
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
11
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K