Terms containing occurrence problem

Subject	English	Russian
math.	clarify the reasons for the occurrence of secular terms it is useful to consider a problem which	чтобы объяснить причины наличия вековых членов, полезно рассмотреть задачу, когда ...
math.	clarify the reasons for the occurrence of secular terms it is useful to consider a problem which	возникновение секулярных членов
math.	occurrence problem	проблема вхождения