用适当的符号填空 (1)a_{a,b,c}; (2)0_{x|x2=0}; (3)∅_{x∈R|x2+1=0}; (4){0,1}_N; (5){0}_{x|x2=x}; (6){2,1}_{x|x2-3x+2=0}.

问题描述:

用适当的符号填空
(1)a______{a,b,c};
(2)0______{x|x2=0};
(3)∅______{x∈R|x2+1=0};
(4){0,1}______N;
(5){0}______{x|x2=x};
(6){2,1}______{x|x2-3x+2=0}.

(1)a∈{a,b,c};
(2)0∈{x|x2=0}={0};
(3)∅={x∈R|x2+1=0};这是因为{x∈R|x2+1=0}=∅;
(4){0,1}⊊N;
(5){0}⊊{x|x2=x};这是因为{0,1};
(6){2,1}={x|x2-3x+2=0}.这是因为{x|x2-3x+2=0}={1,2}.
故答案为:∈、∈=、⊊、⊊、=