Thread: 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

about the x-axis

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

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.

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

about the x-axis

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.

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?

Originally Posted by abilitiesz

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

Yes, times pi.

Originally Posted by rn443

Yes, times pi.

Ohh ok. I'll try it now. Thank you

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?

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?

Please show all your working so that it can be reviewed.