2.18. Where are the following functions differentiable? Where are they holomorphic? Determine their derivatives at points where they are differentiable. (a) f(z) = e-xe-iy (b) f(z) =2x+ixy² (c) f(z) = x²+iy² (d) f(z) = exe-iy (e) f(z) = cosx cosh y – isin x sinh y (f) f(z) = Imz (g) f(z) =|z|2 = x² + y² (h) f(z) = z Imz (i) f(z) = ix+1 у (j) f(z) =4(Rez) (Imz) - i(z)² (k) f(z) = 2xy-i(x + y)² (1) f(z) = z²-z²