response. You must b' include mathematical justification or example(s) illustfdi! 1. Answer True or false for each of the following and then give justification for your answer. An answer of True or false without justification will receive No credit. (a) If f (x,y) is a function and u = (1, 1), then Daf (x, y) = Vf (1, 1) . u is the directional derivative of the function f (r, y) in the direction of the vector ii (b ) lim f (r, 1) = L exists , then f (3, ] ) = Liss - 17