# Maple 15 giving me a headache

1. Sep 29, 2011

### flyingpig

1. The problem statement, all variables and given/known data

You know, you think by the fifteen verison, they could do something right.

I am trying to make a contour plot of $$z = f(x,y) = x^3 - 2xy$$

So I typed the following

Code (Text):
f := (x,y) -> x^3 - 2xy

with(plots):

contourplot(f(x, y), x = -20 .. 20, y = -20 .. 20, contours = [-2, -1, 0, 1, 2])

It gave me an error saying

Error, (in plot/iplot2d/levelcurve) could not evaluate expression