Question

Determine how many elements there are in Dn. Your proof should provide some reasoning as to why you feel as though you’ve counted all such elements.

Note: The analysis carried out above for a square can similarly be done for an equilateral triangle or regular pentagon or, indeed, any regular n-gon (n >,or equal to 3). The corresponding group is denoted by Dn and is called the dihedral group of order 2n.

Answer 1

So no of elements in Dn=2n

For example