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.