问题描述:
1.Does formula f(x)=1/(x²-2) define a function f:R->R?A function Z->R?
2.If there are 2187 function f:A->B and |B|=3.What is |A|?
3.Give an example of a function f:A->B and A1,A2 in the A for which f(A1∩A2) ≠ f(A1)∩f(A2)
4.If A={1,2,3,4,5} and there are 6720 injective functions f:A->B,what is |B|?
2.If there are 2187 function f:A->B and |B|=3.What is |A|?
3.Give an example of a function f:A->B and A1,A2 in the A for which f(A1∩A2) ≠ f(A1)∩f(A2)
4.If A={1,2,3,4,5} and there are 6720 injective functions f:A->B,what is |B|?
问题解答:
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