# Finding the volume of a solid when the solid is a region rotated around a line

• jlt90
In summary, the problem asks to find the volume of a solid obtained by rotating the region bounded by the curves y = x^(6) and y = 1 around the axis y = 2. The region is fin-shaped and is rotated to form a cylinder with missing inside and flat sides. The thickness of the cylinder is delta y and the radius is 2-y, with a circumference of 2pi(2-y). The height of the cylinder is y^(1/6). The integral set up to solve the problem is 0 to 1 of 2pi(2-y)y^(1/6)dy, which gives the wrong answer of 2pi(12/7-6/13). However, the

## Homework Statement

Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis.

y = x^(6), y = 1 about y = 2

## The Attempt at a Solution

So i drew a picture and found the region to be fin shaped from 0 to 1 on both the x and y axis. I then rotated it around y=2 to get a cylinder with a missing inside with flat sides and an outside that is curved. I believe the thickness of these cylinders is delta y, so I'm putting everything in terms of y. I then find the radius to be 2-y, since the center of the cylinder is at y=2 and at y=0 the radius is 2, at y=1 it is 1. So that gives me a circumference of 2pi(2-y). Next I find the height, which my picture shows as the x values when x=y^(1/6), so my h=y^(1/6). I am now able to set up my integral so that 0int1 2pi(2-y)y^(1/6)dy. When I evaluate this, I come up 2pi(12/7-6/13) which is the wrong answer. Can someone please tell me where I went wrong?

I found where I made my mistake :) So no need to help me anymore. Thanks anyways.