“…The Liénard second order differential equation (1) can be written as the equivalent planar differential system When F (x) and g(x) are polynomial functions in the variable x, the Liénard differential system (2) is called the generalized polynomial Liénard differential system has been studied extensively, see [14,38,41] for center conditions, [13,16,21,22,27,37] for the number of limit cycles, [1,40] for the amplitude of limit cycles, [15,26] for integrability conditions, [38,39] for isochronous conditions, and [2,3,17] for global phase portraits and bifurcation diagrams.…”