The function is .

Region bounded by the surface of square with vertices and .

Surface area:

If and its first partial derivative are continuous on the closed region in the -plane then the area of the surface is given by over is defined as

Surface area = .

                       =

Region bounded by the vertices of square:

The function is .

Apply partial derivative with respect to x.

Apply partial derivative with respect to y to the function .

Consider .

The surface area :

Integration formula: .

The surface area of the function is .