It has been a while since I posted the question Treacherous Euler-Lagrange equation. I have read the suggested text. But I was told that I shouldn't need Jacobi amplitude function and other beasties of the sort to solve the problem due to the non-arbitrary limits/boundary conditions. So I would really appreciate some help in finding the way! Here is a restatement of the problem:
$$y^{\prime\prime}(x) = \sin y(x)$$ subjected to boundary conditions $$\lim_{x\to-\infty} y(x) =0$$ $$\lim_{x\to+\infty} y(x) = 2\pi$$
Thanks in advance!
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