Register to reply

(tricky) first order ODE

by mmh37
Tags: order, tricky
Share this thread:
Apr15-06, 09:04 AM
P: 59
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
Attached Thumbnails
Phys.Org News Partner Science news on
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
Apr15-06, 02:09 PM
Astronuc's Avatar
P: 21,885
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

Register to reply

Related Discussions
Solving a PDE : 2 order in time, 4 order in space, mixed derivatives Differential Equations 20
My tricky wave problem. ehh its probably not tricky. Introductory Physics Homework 15
Under damp ing spring, eigen, 2-nd order eqn as 2 1-st order in matrix form. Calculus & Beyond Homework 1
Reducing 2nd order to 1st order type question Differential Equations 4
Tricky Tricky little Identities General Math 2