For a generalized pendulum equation we estimate the number of periodic solutions from below using lower and upper solutions and from above using a complex equation and Jensen’s inequality.
@article{107951,
author = {Zbyn\v ek Kub\'a\v cek and Boris Rudolf},
title = {On the number of periodic solutions of a generalized pendulum equation},
journal = {Archivum Mathematicum},
volume = {041},
year = {2005},
pages = {197-208},
zbl = {1117.34041},
mrnumber = {2164670},
language = {en},
url = {http://dml.mathdoc.fr/item/107951}
}
Kubáček, Zbyněk; Rudolf, Boris. On the number of periodic solutions of a generalized pendulum equation. Archivum Mathematicum, Tome 041 (2005) pp. 197-208. http://gdmltest.u-ga.fr/item/107951/
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