# Volumes

• Jul 8th 2008, 09:38 AM
JonathanEyoon
Volumes
Find the volume obtained by rotating the region bounded
by the given curves about the specified line. Sketch the
region, the solid, and a typical disk, washer, or shell.

x =y−y2 , x=0; about y-axis

Now I graphed this by hand and got the graph below. Now the question is saying to rotate it about the y-axis. Normally i'm given two boundary points but it seems I only have one which is x = 0. I was wondering how do I go about doing this.

Is my graph drawn wrong?
• Jul 8th 2008, 10:43 AM
Soroban
Hello, JonathanEyoon!

Quote:

Find the volume obtained by rotating the region bounded
by the given curves about the specified line. Sketch the
region, the solid, and a typical disk, washer, or shell.

. . $\displaystyle x \:=\:y-y^2,\;x\,=\,0;\text{ about }y\text{-axis}$

Is my graph drawn wrong? . . . . yes

Code:

            |       *    |1             *             |::::*             |::::::*             |:::::::*             |::::::*             |::::*     - - - - * - - - - -       *    |0             |

Now try it . . .

• Jul 8th 2008, 12:16 PM
JonathanEyoon
I thought it was the graph. Thanks alot I appreciate it !!