5. (a) Let CEC and 0 = 0 + 0i. Derive a complex equation for the rotaion Rca(z). (Hint. Use the fact that Rca Tc RoaT_c.). O (b) Show that the isometry f(2)= ei +2i, with 0 = , is a rotation by rewrite f(z) in the form in part (a). In other words find the C and a in (a). (Note that f is a rotation (by 90) followed by a translation. Thus this question verifies Thm 5.20221 in Hvidsten.)