南昌大学信号与系统题库计算题

2 . ? ()_____________1Р 7(1 - 0.5 cos Q)2 + (0.5 sin Q)2 ,1.25-cos QР Re(z)Р 3 .  !(z)"#$%0.5&- 0 . 4 '()*+,-./0123/0-45Р 6/0789":Р 7 . 2 8 <=>23?@/0"ABCD1EР y (`) - y (F-1) ~2 y (n-2)=x (`) +2x(n-2)Р <=y (-1) =2, y (0) =2,x(!)=!(!)-IJZ KLMNOPQRSTU(!)VOР WXRSY(Z)[Р - 1 3 >Р \]E % ( " ) = 2n + l !(“)Р y ,.(n) = 2 rt+l- ( - i r ( n > 0 )Р z