Question 9 (15 marks) consider the integral where f = (3y,_xz,_yz2) and where s is the portion of the surface 2z = z2-+ u2 below the plane ? 2. (a) calculate the given integral directly using cylindrical coordinates (b) now calculate the given integral using stokes' theorem. question 10 (10 marks) (a) let s be the solid determined by 1 x2 + y2 +z2-4 and let f-# zi + (2y + z)j + (z + 2.2)k. evaluate f ds. as (b) let w be a solid in r3 with surface boundary ow, and let f be a scalar field in r3. prove that ow