how to plot non-quadratic function

x0=[2,0];
fun=@(x) x(1)^3-16*x(1)+2*x(2)-3*x(2)^2 %this is my objective function
x = fminsearch(fun,x0)
contour(fun,[-5 5])

When i plot this function i'm getting this error "Input arguments must be numeric or objects which can be converted to double."

Can anyone tell, what is the problem

[Rik]

What do you mean with a contour if you only have a function of one variable? It usually only makes sense to talk about contours if you have a function of two variables.

You error occurs because ezcontour expects a function with two inputs.

[RAHUL KUMAR]

so which command i use for contour plot