10 (a) The complex number u is given by u = −3 – (2√10)i. Showing all necessary working and without using a calculator, find the square roots of u. Give your answers in the form a + ib, where the numbers a and b are real and exact. [5] (b) On a sketch of an Argand diagram shade the region whose points represent complex numbers z satisfying the inequalities |z – 3 – i| ≤ 3, argz > ¦π and Imz ≥ 2, where Im z denotes the imaginary part of the complex number z. [5]