摘要

This article deals with integral boundary value problems of the second-order differential equations @@@ {u ''(t) + a(t)u'(t) + b(t)u(t) + f(t,u(t)) = 0, t is an element of J(+), @@@ u(0) = integral(1)(0) g(s)u(s)ds, u(1) = integral(1)(0) h(s)u(s)ds, @@@ where a is an element of C(J), b is an element of C(J, R-), f is an element of C(J(+) x R+, R+) and g, h is an element of L-1(J) are nonnegative. The result of the existence of two positive solutions is established by virtue of fixed point index theory on cones. Especially, the nonlinearity f permits the singularity on the space variable.