一阶方程 meaning in English

first order equation

Beyond the usual method , the one dimensional equation was expressed in the form of ( the equation is abbreviated ) , which then was introduced by middle varible ( the equation is abbreviated ) , so that the same solution of initial value problem by the characteristic curve method of the first order equations ( the equation is abbreviated ) and ( the equation is abbreviated ) was abtained
摘要对一维非齐次波动方程的始值问题在传统的叠加原理、达朗贝尔公式、齐次化原理的方法之外，完全用特征线方法，先将方程表示为(方程式略)的形式，进而引入中间变量(方程式略) ，得以用一阶方程(方程式略)的特征线方法，推导出维该始植问题的与传统方法相同的解。