How to draw a contour map for a given function

Question

Hi guys...

 

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.........??

Answer 1

I would recommend the drawing engine at Wolfram Alpha (www.wolframalpha.com).

 

Type in "plot z = x^3 - 6x^2 - y^2" and it will draw it for you.