# Perturbation problem

This is a mathematica exercise that I have to do, where $y(x) = x - \epsilon \sin(2y)$ and it wants me to express the solution $y$ of the equation as a power series in $\epsilon$.

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And what is the question? –  Andrew Jun 15 '12 at 7:00
Note that this is the Kepler equation; much has been written about this. –  Guess who it is. Jun 15 '12 at 7:24
Thank you. I'll look this up. –  user8603 Jun 15 '12 at 7:36
I don't see any derivatives, so I removed the "differential equations" tag. –  Gerry Myerson Jun 15 '12 at 10:55
I am eager to know a solution... –  Fischer Oct 10 '12 at 22:16