3 3 I. 3. Let f(x, y) = x + y 3xy+1. Note that the critical - 2 points of f(x, y) on R are (0,0) and (1, 1). What is the absolute maximum of f(x, y) in the triangle with corners (0, 1), (1, 0) and (1, 1)? (a) 1 (b) 2 (c) 3 (d) de 4 (e) 5