In: Advanced Math
(a) Let n = 2k be an even integer. Show that x = rk is an element of order 2 which commutes with every element of Dn.
(b) Let n = 2k be an even integer. Show that x = rk is the unique non-identity element which commutes with every element of Dn.
(c) If n is an odd integer, show that the identity is the only element of Dn which commutes with every element of Dn.