来自郭中华的问题
1.Doesformulaf(x)=1/(x²-2)defineafunctionf:R->R?AfunctionZ->R?2.Ifthereare2187functionf:A->Band|B|=3.Whatis|A|?3.Giveanexampleofafunctionf:A->BandA1,A2intheAforwhichf(A1∩A2)≠f(A1)∩f(A2)4.IfA={1,2,3,4,5}an
1.Doesformulaf(x)=1/(x²-2)defineafunctionf:R->R?AfunctionZ->R?
2.Ifthereare2187functionf:A->Band|B|=3.Whatis|A|?
3.Giveanexampleofafunctionf:A->BandA1,A2intheAforwhichf(A1∩A2)≠f(A1)∩f(A2)
4.IfA={1,2,3,4,5}andthereare6720injectivefunctionsf:A->B,whatis|B|?
1回答
2020-12-19 00:23