1. Consider the graph of the function f(x, y) = cos(xy). Out[-]= P (i) Find the gradient of f(x, y). (ii) Find all points in the unit disk (i.e. points (x, y) such that 22+y2 1) where the gradient points to the origin. (iii) Suppose we are at the point P (,0) on the surface. If we always move in the direction of the gradient from here, where will we end up? (iv) How long is our track if we do what is described in part (iii)? Write an integral that represents your answer, you don't have to get a number if you don't have a calculator.