Postgraduate Students 《Linear System Theory》 Course Examination 2021 Autumn Test time:100 minutes Test Form: Open-book exam (Note: This page is not answer sheet. Please write your answer on the answer sheet.) 一、Short answers. (10分) 1) How to judge the observability for linear constant system? 2) For continuous linear time-invariant(LTl) systems, what are the sufficient and necessary for arbitrary pole assignment?