另一种是在未解出导数的一阶方程中，在拉格朗日方程、克策洛方程解法的基础上更加广泛的推广。
In unsolved derivative first-order differential equations, this paper is based on Lagrange equation and Clairaut equation, and popularizes them.
表1.1元素含量的术语及其含量界限(程介克，1986)。
Table 1.1 Terms of elements and their content limits (Cheng Kejie, 1986).
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