17. (a) Evaluate dV, where E is the solid enclosed by the ellipsoid x²/a² + y²/b² + z²/c² = 1. Use the transfor- mation x = au, y = bv, z = cw. (b) The earth is not a perfect sphere; rotation has resulted in flattening at the poles. So the shape can be approximated by an ellipsoid with a = b = 6378 km and c = 6356 km. Use part (a) to estimate the volume of the earth. 18. If the solid of Exercise 17(a) has constant density k, find its moment of inertia about the z-axis. Answer to 17(a): Answer to 17(b), rounded to 2 decimal places: Answer to 18: × 1012 km³