> with(plots):

> 4(a):f:=x*y^3-y*x^3;

> plot3d(x*y^3-y*x^3,x=-10..10,y=-10..10,colour=black,style=wireframe,axes=framed,orientation=[60,45]);

> 4(b):plot3d(x*y^3-y*x^3,x=-10..10,y=-10..10,colour=black,style=contour,axes=boxed,orientation=[90,0]);

> 5(a):f:=x*y^2-x^3;plot3d(x*y^2-x^3,x=-10..10,y=-10..10,colour=black,style=wireframe,axes=framed,orientation=[30,60]);

> 5(b):plot3d(x*y^2-x^3,x=-100..100,y=-100..100,colour=black,style=contour,axes=boxed,orientation=[90,0]);

>

Department of Mathematics

Trent University