If S is the cyclic subgroup of order n in the dihedral group Dn, show that Dn/S is isomorphic to Z2.
I know I'm supposed to find an epimorphism from Dn to Z2, such that S is its Kernel, so that the quotient group Dn/S will be isomprphic to Z2. But I have no idea of how to find such an isomorphism. Besides, I don't even know what n is, so I have no way of finding the elements of Dn and defining an epimorphism on them.
Any help will be appreciated!!!!