由题意可求得切线方程是y=2-x,根据抛物线和切线作图.
故根据图形德 旋转体的体积=∫π(2-x)²dx-∫π[4(1-x)]dx
=[-π(2-x)³/3]│+[2π(1-x)²]│
=8π/3-2π
=2π/3