Question: Let D consist of all z in the rectangle having vertices ± α i and π ± α i, with α a positive number.
(a) Determine the image of D under the mapping w = cos(z). Sketch D and its image.
(b) Determine the image of D under the mapping w = sin(z). Sketch this image.
(c) Determine the image of D under the mapping w = 2z2. Sketch this image.