# Volume of solids of revolution help..

• Jan 20th 2009, 08:38 PM
Manizzle
Volume of solids of revolution help..
I need help with volumes of solids of revolution.. I am given region R bounded by curves $\displaystyle y = x + 2$, and $\displaystyle y = x^{2}$.
I tried setting it up to figure it out using the disk method, but I am not sure I got the right answer, so I just would like some help setting it up.

O and BTW my answer I got was Pi * 16 and 1/3
• Jan 21st 2009, 09:00 AM
Jester
Quote:

Originally Posted by Manizzle
I need help with volumes of solids of revolution.. I am given region R bounded by curves $\displaystyle y = x + 2$, and $\displaystyle y = x^{2}$.
I tried setting it up to figure it out using the disk method, but I am not sure I got the right answer, so I just would like some help setting it up.

O and BTW my answer I got was Pi * 16 and 1/3

The curves intersect at $\displaystyle x = -1,\; 2$

$\displaystyle V = \pi \int_{-1}^2 (x+2)^2 - x^4\; dx = \frac{72 \pi}{5}$