Let f(x,y)=xy (a) Describe explicitly the x and y slices of f. (That is, if x=k, what is Γ(f(k,y)) and similarly for y=k ) (b) Describe the level set of f for z=0. (c) Consider the restriction of f(x,y) to the lines y=λx where λ∈R−{0}. What is the graph of f over these lines? (d) Sketch part of the graph of f based on the information you found in parts (a)−(c).