Paper 1, Section II, G
Part IB, 2013
(i) Consider the group of all 2 by 2 matrices with entries in and non-zero determinant. Let be its subgroup consisting of all diagonal matrices, and be the normaliser of in . Show that is generated by and , and determine the quotient group .
(ii) Now let be a prime number, and be the field of integers modulo . Consider the group as above but with entries in , and define and similarly. Find the order of the group .