Can someone help me? (volume of solid of revolution)

[mathman1]

I am struggling on a problem I need to turn in in my calc class tonight. THis is the only one I am stuck on. Can someone assist me?

Find the volume of the solid of revolution formed by rotating about the x-axis the region bounded by the curves.

y = e^x, y = 0, x = -3, x = 1

 

[skeeter]

\(\displaystyle V = \pi \int_{-3}^1 (e^x)^2 dx\)

 

[Jeffy]

π^2(e^1 - e^-3)

 

[tkhunny]

What are your thoughts? dx will require only one integral. dy will take two (or one plus some solid geometry). If you solved all the others, what is different about this one?

Volume of a Right Circular Cylinder is pi*(r^2)*h

Differentiate with respect to r: 2*pi*r*h - Then set up the integration along r
Differentiate with respect to h: pi*r^2 - Then set up the integration along h

The same, glorious, unique answer should be the result in each case.

skeeter gave you one.

 

[tkhunny]

π^2(e^1 - e^-3)

pi^2? No. Try again. Be carefult, this time.

 

[Jeffy]

opps my bad n/2 (e^1 - e^-3)

 

[tkhunny]

Yo, consortium of answer stealers and never-show-any-work-or-effort-ers. Why don't you stop this game. We're still trying to help you after all this time and you're still just playing your little game. Please stop it.

 

[tkhunny]

opps my bad n/2 (e^1 - e^-3)

Still no. Quit guessing.