### the definition of quaternion group

(a) Show that the relations a^4 = 1, b^2 = a^2 and b^(-1)ab = a^(-1) define a group of order 8. (It is called the "quaternion group".) (b) Show that this group is not isomporphic to Î"4 (also of order 8). Please see the attachment for more precise text description.