y^2y"=y'
This seems to be a very difficult problem, you may do best to post this in the differential equations subsection and wait for someone who knows how to solve non-linear DE's.
y^2y" = y' i wonder, assume: \[ y = \sum_{n=0}~~ a_nx^n\] \[y'=\sum_{n=1}a_n~nx^{n-1}\] \[y''=\sum_{n=2}a_n~n(n-1)x^{n-2}\]
i wonder how y^2 would work out, it looks to be some monsterous form of \[\sum_{k=0}^ia_k\left(\sum_{n=0}^ia_nx_n\right)\]
*x^n that is, not x_n
y=0,1,-1
hmmm, i wonder of this is correct for y^2 :) \[\left(\sum_{n=0}^{\infty}a_nx^n\right)^2=\frac{\prod_{n=0}^{\infty}(a_n)^2}{(1-x)^2}\]
oh I didn't think to use a power series, good idea :)
its a nice idea, but im not sure how practical it is ;)
http://www.wolframalpha.com/input/?i=y%5E2+y%27%27-y%27%3D0 it definantly doesnt have a nice solution ;)
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