Let QUESTION 9 1 f(x, y) = e (a). Find the domain of f. (b). Determine whether the values 0, 1, and -1 are in the range of f. Justify your answer. (c). Find and sketch the level curves f(x, y) = and f(x, y) = 2. You may draw e all of them in the same plane. (d). Compute the following limit, or show that it doesn't exist. Justify your answer. lim f(x, y) (x,y)(0,0) (e). (Optional; extra credit, 5 points.) Find the range of f. Justify your answer.