【1】A={4,5,7,9},B={3,4,7,8,9},U=A∪B,则CU(A∩B)的元素共有(A)。(A)3个 (B)4个 (C)5个 (D)6个【解】U={3,4,5,7,8,9}, A∩B={4,7,9} ,则|CU(A∩B)|=6-3=3. 【2】(z的共轭)/(1+i)=2+i,则z=(B)。(A)-1+3i (B)1-3i (C)3+i (D)3-i【解】(z的共轭)=(1+i)(2+i)=1+3i;于是z=1-3i.【3】不等式|x+1|/|x-1|1} (B){x|0<x<1} (C){-1<x<0|} (D){x|x<0}【解1】...
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