# Volumes of revolution

1. May 31, 2009

### DeanBH

so i have y = 1/sqroot(3x+2)

find volume when rotated around x, regions are x=2 and x=0

equation needed: V= integral Pi*y^2*dx

so.

i do intergral pi* (1/sqroot(3x+2))^2 * dx

so i get pi integral 1/(3x+2) dx

so how do i integrate 1/sqroot(3x+2) ?

can someone take me though it , because i know theres meant to be a constant near the ln, but i don't know how to find it.

thanks, sorry if it's explained bad

2. May 31, 2009

### rock.freak667

Try putting u=3x+2