Maximum number of limit cycles for Abel equation having coefficients with linear trigonometric functions

Xiangqin Yu, Jianfeng Huang, Changjian Liu

This paper devotes to the study of the classical Abel equation $\frac{dx}{dt}=g(t)x^3+f(t)x^2$, where $g(t)$ and $f(t)$ are trigonometric polynomials of degree $m\ge 1$. We are…