Xy t,y)=4 +y#0 0,else then, the directional derivative at c=(0, 0) in the directio u = (a, a) is/are (a) flc, u) =2,a, #0 a (b) flc, u) =0, a, = 0 (c) flc, u) =

xy T,y)=4 +y#0 0,else Then, the directional derivative at c=(0, 0) in the directio U = (a, a) is/are (a) flc, u) =2,a, #0 a (b) flc, u) =0, a, = 0 (C) flc, u) = d23 (d) None of these