Cho hình phẳng (H) giới hạn bởi

Ta có\(\frac{1}{3}x3 - x2 = 0 \Leftrightarrow \left[ {\begin{array}{*{20}{c}}{x = 0}\\{x = 3}\end{array}} \right.\)

\[V = \pi \mathop \smallint \limits_0^3 {\left( {\frac{1}{3}{x^3} - {x^2}} \right)^2}d{\rm{x\;}} = \pi \mathop \smallint \limits_0^3 \left( {\frac{1}{9}{x^6} - \frac{2}{3}{x^5} + {x^4}} \right)dx\]

\( = \pi \left( {\frac{1}{{63}}{x^7} - \frac{1}{9}{x^6} + \frac{1}{5}{x^5}} \right)\left| {_0^3} \right. = \frac{{81}}{{35}}\pi \)