A.{1,-2j,-3,4j}B.{1,2j,-3,-4j}C.{2,3,4,1}D.{4,1,2,3}
A.0B.1C.2D.4
A.線性移不變系統(tǒng)B.非線性移不變系統(tǒng)C.線性移變系統(tǒng)D.非線性移變系統(tǒng)