Exercise · ZW-CYCLIC-GROUP-006 · ★★☆ Intermediate
How many elements does the subgroup of \((\mathbb{Z}_{24},+)\) generated by \(9\) and \(15\) have?
Choose one option.
Show answer
- C. 8
Explanation
The subgroup generated by \(9\), \(15\) and \(24\) is generated by \(\gcd(9,15,24)=3\), so it equals \(\langle 3\rangle\), of order \(24/3=8\).
Review the concept: Cyclic group
A cyclic group is a group \(G\) with an element \(g\), called a generator, such that every element of \(G\) is a power of \(g\).
\[G=\langle g\rangle=\{\,g^k : k\in\mathbb{Z}\,\}\]
More practice problems: cyclic group
- ZW-CYCLIC-GROUP-001 How many generators does the cyclic group (ℤ_12,+) have?
- ZW-CYCLIC-GROUP-002 Which of the following elements generates (ℤ_10,+)?
- ZW-CYCLIC-GROUP-003 Which of the following groups is NOT cyclic?
- ZW-CYCLIC-GROUP-004 How many subgroups does (ℤ_18,+) have?
- ZW-CYCLIC-GROUP-005 Which of the following elements generates the group (ℤ_7^*,·)?
- ZW-CYCLIC-GROUP-007 Which of the following statements is true?
- ZW-CYCLIC-GROUP-008 How many elements of order 4 does (ℤ_20,+) have?
- ZW-CYCLIC-GROUP-009 Let G=langle grangle be an infinite cyclic group. How many generators does G have?