First Order Non-Linear Differential Equation

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SUMMARY

The discussion centers on solving the first-order non-linear differential equation given by (x+y)dx-(x-y)dy=0. The solution is derived as c=arctan^-1(y/x)-(1/2)*ln(x^2+y^2). A key substitution method is suggested, where y(x)=xv(x) transforms the equation into a solvable form. Participants also inquire about strategies for determining appropriate substitutions for similar differential equations.

PREREQUISITES
  • Understanding of first-order differential equations
  • Familiarity with substitution methods in differential equations
  • Knowledge of inverse trigonometric functions
  • Basic logarithmic properties
NEXT STEPS
  • Research substitution techniques for solving non-linear differential equations
  • Study the application of the arctangent function in differential equations
  • Explore the method of integrating factors for first-order equations
  • Learn about the geometric interpretation of differential equations
USEFUL FOR

Students studying differential equations, mathematics educators, and anyone seeking to deepen their understanding of non-linear differential equations and solution techniques.

Nathan W0
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Homework Statement


(x+y)dx-(x-y)dy=0


Homework Equations





The Attempt at a Solution


The solution is c=arctan^-1(y/x)-(1/2)*ln(x^2+y^2) but I don't know how to get the answer. If someone could explain how to solve the above DE, that would be great.
 
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The DE is of te form:
[tex] \frac{dy}{dx}=\frac{x+y}{x-y}[/tex]
Use the following substitution [tex]y(x)=xv(x)[/tex] The equation will become solvable.

Mat
 
Oh, Okay I understand it now. Is there any way to know what substitution you would need to use?
 

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