With Zero Distribution Of Positive Or Negative Delay Differential Equations

In this paper, we study the distance of zero points for differential equations with positive and negative arguments by method of polynomial series, and some more explicit conditions to oscillate are given. First, we give a polynomial series and study its minimum positive zero points, from this, the theorem of delay differential equations with both positive arguments and constant coefficient is obtained, this theorem is more explicit and practicable. Then, we study linear differential equations with variable coefficient and nonlinear differential equations. Some sufficient conditions for this equation to oscillate are given. By the same method, we study the distance of zero points for differential equations with negative arguments.