Find general solution, 1st order ODE

2h2o
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Homework Statement



Find a general solution.

Homework Equations



2x\frac{dy}{dx}+y^{3}e^{-2x}=2xy

The Attempt at a Solution



Looks like a Bernoulli equation to me, after some algebra:

\frac{dy}{dx}+\frac{y^{3}}{2xe^{2x}}=y

\frac{dy}{dx}+\frac{y}{2xe^{2x}}=y^{-1}

so with n=-1
v=y^{2}, y=v^{1/2}, \frac{dy}{dx}=\frac{1}{2}v^{-1/2}\frac{dv}{dx}

\frac{1}{2}v^{-1/2}}\frac{dv}{dx}+\frac{v^{1/2}}{2xe^{2x}}=v^{-1/2}

\frac{1}{2}\frac{dv}{dx}+\frac{v}{2xe^{2x}}=1

\frac{dv}{dx}+\frac{v}{xe^{2x}}=2

Now an integrating factor:

\mu=exp[\int{x^{-1}e^{-2x}dx}]

And that's where I get stuck. This doesn't look like any elementary integral I've learned how to solve, and wolfram|alpha gives me something called the "exponential integral" which we haven't been taught. So I've done something wrong, but I don't see it.

Thanks for any insights.
 
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Ok, I think I found my error: I forgot to divide the dy/dx by y^2 when I obtained y^-1 as the RHS. No wonder I wound up with a nonelementary integral. However, I'm still stuck.

I don't recognize this equation, and manipulating it around trying to "force it" to be in first-order linear, homogeneous, or bernoulli hasn't helped. So I'm stuck.

This is where I am, and don't recognize it:

\frac{dy}{dx}+\frac{y^{3}}{2xe^{2x}}=y
 
Isn't that separable? Split up the differentials?
 
This is just another Bernoulli type ODE isn't it?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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