RT Journal Article T1 Existence of solutions of a second order equation defined on unbounded intervals with integral conditions on the boundary A1 Cabada Fernández, Alberto A1 Khaldi, Rabah K1 Boundary value problems K1 Integral boundary conditions K1 Upper and lower solutions method K1 Existence of solution AB In this paper we shall use the upper and lower solutions method to prove the existence of at least one solution for the second order equation defined on unbounded intervals with integral conditions on the boundary: \begin{equation*} u^{\prime \prime }\left( t\right) -m^{2}u\left( t\right) +f( t,e^{-mt}u\left( t\right) ,e^{-mt}\,u^{\prime }\left( t\right)) =0,\quad \mbox{for all}\;t\in % \left[ 0,+\infty \right) , \label{1.1} \end{equation*} \begin{equation*} \label{1.2} u\left( 0\right) -\frac{1}{m}u^{\prime }\left( 0\right) =\int\limits_{0}^{+\infty }e^{-2ms}u\left( s\right) ds,\underset{% t\rightarrow +\infty }{\lim }{\left\{e^{-mt}u\left( t\right) \right\}} =B, \end{equation*}% where $m>0,m\neq \frac{1}{6},B\in \mathbb{R}$ and $f:\left[ 0,+\infty \right) \times \mathbb{R}^{2}\rightarrow \mathbb{R} $ is a continuous function satisfying a suitable locally $L^1$ bounded condition and a kind of Nagumo's condition with respect to the first derivative. PB Malaya Journal of Matematik SN 2319-3786 YR 2021 FD 2021-06-04 LK https://hdl.handle.net/10347/37954 UL https://hdl.handle.net/10347/37954 LA eng NO Cabada, A., and R. Khaldi. “Existence of Solutions of a Second Order Equation Defined on Unbounded Intervals With Integral Conditions on the Boundary”. Malaya Journal of Matematik, vol. 9, no. 03, July 2021, pp. 117-28, doi:10.26637/mjm0903/006 NO Xunta de Galicia (Spain), project EM2014/032 DS Minerva RD 28 abr 2026