%A Shiping Lu,Shile Zhou,Xingchen Yu %T Periodic Solutions for a Singular Liénard Equation with Sign-Changing Weight Functions %0 Journal Article %D 2021 %J Acta mathematica scientia,Series A %R %P 686-701 %V 41 %N 3 %U {http://121.43.60.238/sxwlxbA/CN/abstract/article_16419.shtml} %8 2021-06-01 %X

In this paper, we study the existence of positive periodic solutions for a singular Liénard equation where $f: (0, +\infty)\rightarrow \mathbb{R} $ is continuous which may have a singularity at $x=0$, $\alpha$ and $\varphi$ are $T$ -periodic functions with $\alpha, \varphi\in L([0, T], \mathbb{R})$, $\mu\in(0, +\infty)$ and $\delta\in(0, 1]$ are constants. The signs of weight functions $\alpha(t)$ and $\varphi(t)$ are allowed to change on $[0, T]$. We prove that the given equation has at least one positive $T$ -periodic solution. The method of proof relies on a continuation theorem of coincidence degree principle.