This paper is concerned with the numerical solution of a system of ordinary di erential equations ODEs y Sy t f t y p on an inter val b subject to boundary conditions g y y b p The ODEs have a coe cient that is singular at t but it is assumed that the boundary value problem BVP has a smooth solution Some popular methods for BVPs evaluate the ODEs at t This paper deals with the practical issues ...

The existence of positive solutions is shown for the third order boundary value problem, u′′′ = f (x,u),0 < x < 1, u(0) = u(1) = u′′(1) = 0, where f (x,y) is singular at x = 0 , x = 1 , y = 0 , and may be singular at y = ∞. The method involves application of a fixed point theorem for operators that are decreasing with respect to a cone. Mathematics subject classification (2010): 34B16, 34B18.

In this paper, we establish some criteria for the existence of positive solutions for certain two point boundary value problems for the singular nonlinear second order equation −(ru ) + qu = λf (t, u ) on a time scale T. As a special case when T = R, our results include those of Erbe and Mathsen [11]. Our results are new in a general time scale setting and can be applied to difference and q-dif...

Let Ω ⊂ RN with N ≥ 2. We consider the equations N ∑ i=1 ui ∂2u ∂xi + p(x) = 0, u|∂Ω = 0, with a1 ≥ a2 ≥ .... ≥ aN ≥ 0 and a1 > aN . We show that if Ω is a convex bounded region in RN , there exists at least one classical solution to this boundary value problem. If the region is not convex, we show the existence of a weak solution. Partial results for the existence of classical solutions for no...