Thank you very much

@Kitonum

 thank you very much , the (ContoursWithLabels) can not be used in maple 18,what is the alternative commed?

thank you very much, but i use maple 18 , the (ContoursWithLabels) can not be used i don't know the alternative commed. If i use the second commed for any function ,how can I determine x and h in  contours=[seq(-x..x,h)]?

thank you very much,

> restart;
> f := proc (x, y) options operator, arrow; sin(x)*cos(y) end proc;
> AVor := 0; DD := .1; N := 1000;
> st := time(); for i from 0 to N do x := i*DD; for j from 0 to N do y := j*DD; AVor := AVor+f(x, y) end do end do; time()-st;
12.028
> AVor;
-96.94743027
> \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\;
>
> f := proc (x, y) options operator, arrow; sin(x)*cos(y) end proc;
> AVor := 0; DD := .1; N := 1000;
> st := time(); for i from 0 to N do x := i*DD; for j from 0 to N do y := j*DD; AVor := AVor+f(x, y) end do end do; time()-st;
13.681
> AVor;
-96.94743027
>

why this different between CPU time (12.028, 13.681) ?

yes, i used suggestions but no change. I do not know what you mean code. this error occurs in the negative decimal numbers.

thank you very much, but i need (2.5-, 1.5-, 0.5-) write as (-2.5, -1.5, -0.5) in plot

f:=(x,y)->[(e)^(-0.96374054* x) (sin(2 *Pi *y) )((-0.96374054)^(2)-4* Pi^(2))]/(2 *Pi) on [-0.5,1.5]²    , why contour plots of this function in maple18 is different on contour plots of this function in matlab?