摘要
By using some differential inequality, a second-order delay differential equation(r(t)x′(t))′ + p(t)x(q(t)) = 0has been investigated and some necessary condition for this equation has a nonoscillatorysolution and some sufficient condition which ensures that all of the solutions of the aboveequation are oscillatory are obtained.
基金
Supported by the National Natural Science Foundation of China(10061004)
Supported by the Natural Sciences Foundation of Yunnan province(2003A0001M)