Use the divergence theorem to calculate the surface integral s f · ds; that is, calculate the flux of f across s. f(x, y, z) = ey tan(z)i + y 6 − x2 j + x sin(y)k, s is the surface of the solid that lies above the xy-plane and below the surface z = 2 − x4 − y4, −1 ≤ x ≤ 1, −1 ≤ y ≤ 1.