Plot3D[{2-(x^2)-(y^2),(E^(-(x^2)))Cos[(x^2)+(y^2)]},{x,-1,1},{y,-1,1}]
N[Integrate[(2-(x^2)-(y^2))-(E^(-(x^2)))Cos[(x^2)+(y^2)],{x,-1,1},{y,-1,1}],4]