questions below:

Evaluate the surface integral II G(x,y,z) do using a parametric description of the surface. S 2 G(x.y,z) = 422, over the hemisphere x2 + y2 + z = 4, z 2 0 E) The value of the surface integral is D. (Type an exact answer, using 1: as needed.) Use a parametrization to find the flux F . n do of F = 3zk across the portion of the sphere x + y + Z" = a where y is positive in the direction away from the origin. The flux is . (Type an exact answer in terms of It.)Find the centroid of the portion of the sphere x + y-+ z- =9a-that lies in the first octant. . . The x-coordinate of the centroid is at (Type an exact answer, using it as needed.) The y-coordinate of the centroid is (Type an exact answer, using it as needed.) The z-coordinate of the centroid is (Type an exact answer, using it as needed.)