# Volume of Rotation

1. Feb 2, 2015

### tree.lee

1. The problem statement, all variables and given/known data

How do you find the volume of the solid obtained by rotating the region bounded by the given curves about the specified lines?

I keep getting a negative number and I"m becoming so frustrated! 11pi/30 is the answer in the textbook. Thank you so very much in advance!

2. Relevant equations

y=x^2
x=y^2

3. The attempt at a solution

Area:
pi[(1-x^2)^2 - (1-x^(1/2))^2)]

Integral:
pi[1-2x^2+x^4-1+2x^(1/2)-x) between x=0 and x= 1

Antiderivative:
pi[(1/5x)^5-(2/3)x^3 + (2/3)x^(3/2)-(1/2)x^2]

Soln:
pi((2/10)-(5/10)) = -3pi/10???????

Last edited by a moderator: Feb 2, 2015
2. Feb 2, 2015

### Staff: Mentor

I edited your post, removing most of the BBcode that you used. Physics Forums rules (https://www.physicsforums.com/threads/physics-forums-global-guidelines.414380/) discourage the overuse of special font styles in topics.

Last edited: Feb 2, 2015
3. Feb 2, 2015

### Staff: Mentor

You have a mistake in the line above. The coefficient 2/3 in the third term is wrong. I get what you reported to be the correct answer.