2) a) Sketch the contour lines of f (x, y) = ex -y in the square -1

x2y2 in the square 1 < x < 1 2) a) Sketch the contour lines of f (x, y) and 1 f y 1. b) Consider the function f (x, y) In(x + y). What is the domain of this function? Sketch the contour lines of the function f (x, y) In(x + y).