Use the top hat function in 2D to show that 8(x) = 8(x)d(y) for x € R². (e) (3 marks) You are given that the Green function of Poisson's equation Au(x) = f(x) in 2D is G(x) = ln |x|/(2T). Show that u(x) = √ Im x - x'\ƒ (x²)dx'. 2π (f) (4 marks) Calculate the Green function of Poisson's equation for the half plane y > 0, with boundary condition G = 0 on y = 0.