Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations

The two-dimensional system of nonlinear differential equations $$ x'' = p(t)y^{\alpha}, \quad y'' = q(t)x^{\beta}\qquad {\textrm{(A)}} $$ with positive exponents $\alpha$ and $\beta$ satisfying $\alpha\beta<1$ is analyzed in the framework of regular variation. Under the assump...

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Main Authors: Jaroslav Jaroš, Takaŝi Kusano
Format: Article
Language:English
Published: University of Szeged 2013-04-01
Series:Electronic Journal of Qualitative Theory of Differential Equations
Subjects:
Online Access:http://www.math.u-szeged.hu/ejqtde/periodica.html?periodica=1&paramtipus_ertek=publication&param_ertek=1892
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author Jaroslav Jaroš
Takaŝi Kusano
author_facet Jaroslav Jaroš
Takaŝi Kusano
author_sort Jaroslav Jaroš
collection DOAJ
description The two-dimensional system of nonlinear differential equations $$ x'' = p(t)y^{\alpha}, \quad y'' = q(t)x^{\beta}\qquad {\textrm{(A)}} $$ with positive exponents $\alpha$ and $\beta$ satisfying $\alpha\beta<1$ is analyzed in the framework of regular variation. Under the assumption that $p(t)$ and $q(t)$ are nearly regularly varying it is shown that system (A) may possess three types of positive solutions $(x(t),y(t))$ which are strongly monotone in the sense that (i) both components are strongly decreasing, (ii) both components are strongly increasing, and (iii) one of the components is strongly decreasing, while the other is strongly increasing. The solutions in question are sought in the three classes of nearly regularly varying functions of positive or negative indices. It is also shown that if we make a stronger assumption that $p(t)$ and $q(t)$ are regularly varying, then the solutions from the above three classes are fully regularly varying functions, too.
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spelling doaj.art-af0d35e817714e31a58b40c6705bb1392023-05-09T07:53:03ZengUniversity of SzegedElectronic Journal of Qualitative Theory of Differential Equations1417-38752013-04-0120132312310.14232/ejqtde.2013.1.231892Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equationsJaroslav Jaroš0Takaŝi Kusano1Comenius University, Bratislava, SlovakiaHiroshima University, Higashi-Hiroshima, JapanThe two-dimensional system of nonlinear differential equations $$ x'' = p(t)y^{\alpha}, \quad y'' = q(t)x^{\beta}\qquad {\textrm{(A)}} $$ with positive exponents $\alpha$ and $\beta$ satisfying $\alpha\beta<1$ is analyzed in the framework of regular variation. Under the assumption that $p(t)$ and $q(t)$ are nearly regularly varying it is shown that system (A) may possess three types of positive solutions $(x(t),y(t))$ which are strongly monotone in the sense that (i) both components are strongly decreasing, (ii) both components are strongly increasing, and (iii) one of the components is strongly decreasing, while the other is strongly increasing. The solutions in question are sought in the three classes of nearly regularly varying functions of positive or negative indices. It is also shown that if we make a stronger assumption that $p(t)$ and $q(t)$ are regularly varying, then the solutions from the above three classes are fully regularly varying functions, too.http://www.math.u-szeged.hu/ejqtde/periodica.html?periodica=1&paramtipus_ertek=publication&param_ertek=1892systems of nonlinear differential equationsstrongly increasing (decreasing) solutionsregularly varying functions
spellingShingle Jaroslav Jaroš
Takaŝi Kusano
Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
Electronic Journal of Qualitative Theory of Differential Equations
systems of nonlinear differential equations
strongly increasing (decreasing) solutions
regularly varying functions
title Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
title_full Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
title_fullStr Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
title_full_unstemmed Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
title_short Asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
title_sort asymptotic behavior of positive solutions of a class of systems of second order nonlinear differential equations
topic systems of nonlinear differential equations
strongly increasing (decreasing) solutions
regularly varying functions
url http://www.math.u-szeged.hu/ejqtde/periodica.html?periodica=1&paramtipus_ertek=publication&param_ertek=1892
work_keys_str_mv AT jaroslavjaros asymptoticbehaviorofpositivesolutionsofaclassofsystemsofsecondordernonlineardifferentialequations
AT takasikusano asymptoticbehaviorofpositivesolutionsofaclassofsystemsofsecondordernonlineardifferentialequations