How to draw a contour map for a given function
I have a function z=x3-6x2-y2 and given to draw a contour map to represent the surface.
I set z to some randomly chosen values and obtained the relevant x and y values.
But I keep on getting almost the same values for x and y when z is set to different vales. And so I cannot sketch a map instead giving me some set of lines which are almost touching each other.
Is there anyway that I can solve my problem.........??