中文说明：
用Matlab实现求偏微分数值解的有限元法。 波动方程是数学中一个常见于静电学、机械工程和理论物理的偏微分方程。
English Description：
The finite element method of partial differential numerical solution is realized by MATLAB. Wave equation is a partial differential equation in mathematics, which is commonly used in electrostatics, mechanical engineering and theoretical physics