Positive solutions of nonlinear differential equations with prescribed decay of the first derivative

An existence and uniqueness result for bounded, positive solutions x(t) of the equation u" + f (t, u, u') = 0, t greater than or equal to t(0) greater than or equal to 0, is established by means of the Banach contraction principle. For such a solution it is shown that alpha(t) less than or equal to x'(t) less than or equal to beta(t), t greater than or equal to t(0), where alpha, beta are given nonnegative, continuous functions which are integrable over [t(0), +infinity). The result complements others known in the literature