In this paper, we discuss when a quarticequation has no real roots, and obtain a necessary and sufficient condition on a quarticequation which has no real roots.
本文讨论了一元四次方程无实根的一些充分、必要条件，并得到了一元四次方程无实根的一个充要条件。
2
The qualitative theory of ordinary differential equations and numerical simulation method are employed to investigate the kink waves of a nonlinear quarticequation.
用微分方程定性理论结合数值模拟方法研究了一类非线性四阶波动方程的纽结波。
3
Given the velocity ratio of S-to P-waves, the depth of reflector and the offset, the horizontal distance between source and the converting point can be determined by solving a quarticequation.