Exact Solutions to Cubic Duffing Equation by Leaf Functions Under Free Vibration

Exact solutions with the initial conditions are presented in the cubic duffing equation. These exact solutions are expressed in terms of the leaf function and the trigonometric function. The leaf functions: $r=sleaf_n(t)$ or $r=cleaf_n(t)$ satisfy the ordinary differential equation: $dx^2/dt^2=-nr^{2n-1}$. The second order differential of the leaf function is equal to $-n$ times the function raised to the $(2n-1)$ power of the leaf function. By using the Leaf functions, the exact solutions of the cubic Duffing equation can be derived under several conditions. In this paper, seven types of the exact solutions are presented based on the leaf functions. This paper reveals the derivation of the seven exact solutions. Finally, the waves based on the exact solutions are visualized by the numerical results in the graphs