1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Dihedral groups

  1. Feb 18, 2009 #1
    My goal is to prove that if n >= 3 then Dn, which is the dihedral group of size n is non-abelian.

    I am stuck, but my attempt at a solution was to show that some the symmetries in Dn are not commutative under composition, but I do not know how to prove that for n cases. My other attempt was to find a isomorphism to Dn and show that its isomorphism is not abelian, but I have no clue where to start from there.

    I would appreciate either an answer, or something to help me get going. Please be precise and I thank you so much in advance.
  2. jcsd
  3. Feb 18, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    In general, a rotation doesn't commute with a reflection.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Similar Threads for Dihedral groups
Are these homomorphisms?