(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Use the method of cylindrical shells to find the volume generated

by rotating the region bounded by the given curves about the

specified axis. Sketch the region and a typical shell.

y = 4x - x^2, y = 3; about x = 1

2. Relevant equations

?

3. The attempt at a solution

int(2*pi*(1-x)*(3-4*x+x^2), x = 0 .. 1) = 11pi/6

This is the only problem on the book that I can't really understand. The correct answer is 8pi/3 according on the odd answers on the back page.

Increasing the upper limit to 2 gives the correct answer. But why? Isn't it I'll just integrate until 1 so I can get a y = 3. Why 2?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Cylindrical Shells

**Physics Forums | Science Articles, Homework Help, Discussion**