Why are these DEs homogeneous?

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SUMMARY

The discussion focuses on the classification of differential equations (DEs) as homogeneous, specifically addressing the equations (x + ye^(y/x))dx - (xe^(y/x))dy = 0 and ydx + x(lnx - lny - 1)dy = 0. Participants express confusion regarding the concept of homogeneity, particularly in relation to the presence of exponents and the substitution methods y=ux or v=xy. The key takeaway is that a DE is considered homogeneous if all terms can be expressed as a function of the same degree, allowing for substitution techniques to simplify the equations.

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Homework Statement


The following DEs are homogeneous and can be solved using a substitution y=ux or v=xy. I can solve them, I'm just don't see how they are homogeneous.

How is it that with there being an exponent (y/x) that this is homogeneous. I don't see how I could pull out t[tex]\alpha[/tex]

(x + ye^(y/x))dx - (xe^(y/x))dy = 0

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Same problem with this one

ydx + x(lnx - lny -1)dy=0

For both, I can see the powers are the same, but I don't think I completely understand what it means to have a homogeneous differential equation.




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The Attempt at a Solution

 
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also this one is bothering me x(dy/dx) = y ln(xy)
 

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