2. [5 points each] Consider the equation y33y=x33x A critical point of an implicit function is a point (x,y) on the graph where the formula for the derivative is zero or undefined. At a critical point, the graph may have a horizontal tangent, a vertical tangent, or nekhen 8) Find an implicit formula for the derivative. Show your work. b) Use part (a) to find the coordinates of critical points where the graph has horizontal tangents. c) Use part (a) to find the coordinates of critical points where the graph has vertical tangents. d) Use part (a) to find the coordinates of critical points where the graph has neither a horizontal tangent nor a vertical tangent