1.Let G be a group.  
Show that the set Aut(G) consisting of all automorphisms of G is a subgroup of Sym(G)
Show that if G is non-abelian, then |Aut(G)|>1.
2.Determine, with justification, the group Aut(Z10) (your answer should include a full table of products). Is it abelian? 
3.Let n‰¥2. Determine, with justification, the index of On(R) in GLn(R)