平面摆非线性振动水平分量方程的建立及其近似解

本文讨论了平面摆在振幅并不是很小情况下的自由运动，推导了运动微分方程在水平方向的投影，用微扰法求解该非线性方程的近似解，并说明运动的频率与振幅有关。

Establishment and Approximate Solution to Horizontal Equation in Case of Nonlinear Oscillation of Plane Pendelum

The phenomena of oscillation are very substantial curriculum in physics and project technology. Usually a method of linear approximation is used for analysis. But, all the natural phenomena are generally nonlinear. This paper canvasses concretely about the plane pendulum's freestyle movement when the amplitude is not very small and then reaches the projection equation at horizontal motion. A perturbation procedure to get approximate solution to nonlinear equation is accepted, which results in the relationship among the frequency and amplitude of movement.