用函数变换法求解二阶欧拉方程

通过“函数变换”将二阶欧拉方程降阶为可积的一阶线性微分方程，从而得到其积分形式的通解，还得到了一类非齐次欧拉方程特解的简单公式。该方法比用“自变量代换”法将欧拉方程转化为常系数线性微分方程进而求其解的过程更简单、更直接。

Solving Euler Equation of 2-Order by the Method of Function Transformation

By the methods of function transformation, non-homogeneous linear differential equations of constant coefficient of 2-order are reduced into integrable linear differential equations of 1-order. It obtains special solution of a kind of special differential equations. This method is more simple and direct than variable replacement method to make Euler equation transform linear differential equation of constant coefficient.