First Order Non-Linear Differential Equation (1 Viewer)

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Nathan W0

1. The problem statement, all variables and given/known data
(x+y)dx-(x-y)dy=0

2. Relevant equations

3. 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.

hunt_mat

Homework Helper
The DE is of te form:
$$\frac{dy}{dx}=\frac{x+y}{x-y}$$
Use the following substitution $$y(x)=xv(x)$$ The equation will become solvable.

Mat

Nathan W0

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

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