∵解方程组z=x²+2y²与z=6-2x²-y²,得x²+y²=2∴所求立体在xoy面上投影区域为D={(x,y)lx²+y²≤2}故 所求立体体积=∫∫[(6-2x²-y²)-(x²+2y²)]dxdy=∫∫[6-...