Terms for subject Mathematics containing occurrence problem

English	Russian
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 ...
clarify the reasons for the occurrence of secular terms it is useful to consider a problem which	возникновение секулярных членов
occurrence problem	проблема вхождения