The number of subgroups of order 25 of an Abelian group of order 50 is ( ).
A: 0
B: 1
C: 2
D: 3
A: 0
B: 1
C: 2
D: 3
举一反三
- The number of elements of order 2 in even order groups must be odd
- Viewing: Number these events from 1-4 in the order they happened.[img=477x327]1803de18453944c.png[/img] A: 1 B: 2 C: 3 D: 4
- 在SQL查询语句中以下正确的子句顺序是？ A: WHERE --- GROUP BY --- HAVING --- ORDER BY B: GROUP BY --- HAVING --- ORDER BY --- WHERE C: WHERE --- HAVING --- GROUP BY --- ORDER BY D: GROUP BY --- ORDER BY --- HAVING --- WHERE
- If a group has at least two elements of order 2, then this group is not cyclic.
- There are following business statements for an information system:①A customer submit 0 or more orders;②An order can only be submitted by one customer. There are two classes in the system “Customer” and “Order”. For each instance of Order Class, there are ____ instance(s) of Customer Class; while for each instance of Customer Class, there are ____ instance(s) of Order Class. A: (1) 1 (2) 1 B: (1) 1 (2) 1 or more C: (1) 1 (2) 0 or more D: (1) 0 or more (2) 1