Solve Differential Eq.: dy/dx= 1/(xy+x^2y^3)

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Discussion Overview

The discussion revolves around methods for solving the differential equation dy/dx = 1/(xy + x^2y^3). Participants explore various approaches and techniques related to first-order differential equations.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant expresses uncertainty about the appropriate method to solve the given differential equation, noting it does not fit familiar forms such as linear, Bernoulli, or separable equations.
  • Another participant proposes a substitution method, suggesting that by letting x = 1/u, the equation can be transformed into a non-homogeneous linear ordinary differential equation (ODE).
  • The same participant indicates that the homogeneous part of the equation is separable, implying a potential pathway for further exploration.
  • Additional comments address the use of LaTeX for formatting mathematical expressions, with advice on how to implement it in the forum.

Areas of Agreement / Disagreement

There is no consensus on the best method to solve the differential equation, as one participant proposes a specific approach while another expresses uncertainty about the methods available.

Contextual Notes

Participants have not fully explored all possible methods for solving the equation, and there may be limitations in their understanding of the equation's structure and properties.

Who May Find This Useful

This discussion may be useful for students or individuals seeking to understand various techniques for solving first-order differential equations, particularly in a homework context.

estalniath
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Hello guys,

Which method can we use to solve the differential equation below?
dy/dx= 1/(xy+x^2y^3)

It doesn't seem to be of any form which I had studied before(linear differential equations,bernoulli,exact differential,homogeneous,seperable equations) for first order differential equations yet it appeared in one of out past examination questions :cry:
 
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It's easy.For me

[tex]\frac{dy}{dx}=\frac{1}{xy+x^{2}y^{3}}[/tex]

Therefore

[tex]\frac{dx}{dy}=yx+y^{3}x^{2}[/tex]

Make the substitution

[tex]x=\frac{1}{u}[/tex]

,under which

[tex]\frac{dx}{dy}=-\frac{1}{u^{2}}\frac{du}{dy}[/tex]

Therefore the new ODE is

[tex]-\frac{1}{u^{2}}\frac{du}{dy}=\frac{y}{u}+y^{3}\frac{1}{u^{2}}[/tex]

equivalently

[tex]\frac{du}{dy}=-yu-y^{3}[/tex]

I trust you can take it from here.It's an nonhomegenous linear ODE...(the homogenous eq is separable).


Daniel.
 
Wow! That was a fast reply. =) Thank you for replying and how do you type the mathematical equations in between? I don't seem to see any functions in this thread which allows us to type mathematical functions?
 
Write formulas in latex code and use preview option for checking it b4 clicking submit.

Daniel.
 
I see. Thank you for the advice =)
 

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