Hello, i'm new around here. I was having trouble with a problem, i thought i could look for help on the net. Anyway here's the problem: Calculate the volume of a solid obtained by the rotation around Ox of all points (x,y) in RxR where y >= x*x, y <= square root of x and y <= 1/(8x). What I did was: 1/(8x) = x*x so x = 1/2 1/(8x) = square root of x so x = 1/4 And then i found the integrals which are: + Integral of square root of x times dx between 0 and 1/4 - Integral of x * x times dx between 0 and 1/4 + Integral of 1/(8x) times dx between 1/4 and 1/2 - Integral of x * x times dx between 1/4 and 1/2 So this gives me the area, but i have no idea on how to calculate the volume. Hope someone can help. Tks... And i'm sorry about my english, this is my first time writing math in english.