Problem 4. (12.626) The gure shows the surface created when the cylinder J12 + 22 =1 intersects the cylinder at2 + 22 =1 . Find the area of this surface. [Hint Find the surface area of one of the eight identical pieces of this surface, e.g. the part above the triangular region bounded by the lines y = x , y = x , and x = 1 .]