# Find the volume of the solid formed by rotating the region..

• Oct 22nd 2009, 06:45 PM
abilitiesz
Find the volume of the solid formed by rotating the region..
Hello,

I need help with this question that i've been trying to solve for 15-20 mins and keep getting the wrong answer.

Find the volume formed by rotating the region enclosed by:

y=e^3x+5
y=0
x=0
x= 0.4

Can anyone show me the steps on how to solve it so I can see what mistakes i'm doing? Thank you.
• Oct 22nd 2009, 07:01 PM
Arturo_026
try graphing each of the functions and lines you were given
and see what sector lies between them and use the formula for volume of solids with the right intervals.
• Oct 22nd 2009, 07:09 PM
rn443
Quote:

Originally Posted by abilitiesz
Hello,

I need help with this question that i've been trying to solve for 15-20 mins and keep getting the wrong answer.

Find the volume formed by rotating the region enclosed by:

y=e^3x+5
y=0
x=0
x= 0.4

Can anyone show me the steps on how to solve it so I can see what mistakes i'm doing? Thank you.

Calculate pi*y^2, and integrate it from 0 to .4.
• Oct 22nd 2009, 07:15 PM
abilitiesz
Quote:

Originally Posted by rn443
Calculate pi*y^2, and integrate it from 0 to .4.

Do I plug in e^3x +5 and square it? Then get the dy of it?
• Oct 22nd 2009, 07:23 PM
rn443
Quote:

Originally Posted by abilitiesz
Do I plug in e^3x +5 and square it? Then get the dy of it?

Yes, times pi.
• Oct 22nd 2009, 07:25 PM
abilitiesz
Quote:

Originally Posted by rn443
Yes, times pi.

Ohh ok. I'll try it now. Thank you :)
• Oct 22nd 2009, 07:38 PM
abilitiesz
I still can't seem to get it. I think i'm doing something arithmetically wrong when plugging it in. Can someone show me how you do it so I can check what i'm doing wrong? Thank you.

I got 72.15042729. But, it says i'm still wrong. Can anyone show me how to do it properly?
• Oct 23rd 2009, 02:43 AM
mr fantastic
Quote:

Originally Posted by abilitiesz
I still can't seem to get it. I think i'm doing something arithmetically wrong when plugging it in. Can someone show me how you do it so I can check what i'm doing wrong? Thank you.

I got 72.15042729. But, it says i'm still wrong. Can anyone show me how to do it properly?