investigate the family of functions f(x,y) = e^(c+x^2 + y^2). how does the shape of the graph depend on c? using maple

graph the surface, tangent line and normal line for:

xy + yz + xz = 3 (1,1,1). choose the domain so that avoid the extraneous vertical planes.

the paraboloid  z = 6-x-x^2 -2y^2 intersects the plane x=1 in a parabola. graph the paraboloid, the parabola and the tangent line at point (1,2,-4). any help.

i'm totally new with Maple so i really need help with this problem

graph the fucntion using various domains and viewpoints. plot some contour lines of the same function and compare with the graph.

f(x,y) = x*y^2 - x^3

thanks