y 2 = x , x = 2 y {\displaystyle y^{2}=x,x=2y}
∫ 0 4 π [ 2 y − y 2 ] d x = π [ 2 ( 4 ) − ( 4 ) 2 ] = π [ 8 − 16 ] = 64 π 15 {\displaystyle {\begin{aligned}\int _{0}^{4}\pi [2y-y^{2}]dx&=\pi [2(4)-(4)^{2}]\\[2ex]&=\pi [8-16]\\[2ex]&={\frac {64\pi }{15}}\end{aligned}}}
![{\displaystyle {\begin{aligned}\int _{0}^{4}\pi [2y-y^{2}]dx&=\pi [2(4)-(4)^{2}]\\[2ex]&=\pi [8-16]\\[2ex]&={\frac {64\pi }{15}}\end{aligned}}}](https://en.wikipedia.org/api/rest_v1/media/math/render/svg/c32b51ec9f0fdc8ae163a742a3400770da5a3fcd)