When Z is assigned the meaning of a complex variable, problem of "closed form" of formal power series emerges.
当指定Z为复数变元时，就有了形式幂级数的“变换”函数，即闭合形式的问题。
Stress intensity factors at the craek tips are computed by complex variable functions and perturbation method and formulas are given in power series forms.
采用复变函数及摄动方法，最后以幂级数形式给出应力强度因子的计算公式。
Stress intensity factors at the craek tips are computed by complex variable functions and perturbation method and formulas are given in power series forms.
采用复变函数及摄动方法，最后以幂级数形式给出应力强度因子的计算公式。
应用推荐