calculus
posted by Tina .
Consider the solid obtained by rotating the region bounded by the given curves about the xaxis.
y = 9  9x^2 , y = 0
Find the volume V of this solid.
Sketch the region, the solid, and a typical disk or washer.
Any help or tips would be greatly appreciated; not sure how to work it :/

The curve intersects the xaxis at (1,0) and (1,0).
Volume = π[integral] y^2 dx from 1 to 1
or by symmetry
= 2π[integral] (99x^2)^2 dx from 0 to 1
= 2π[integral] (81  162x^2 + 81x^4) dx from 0 to 1
= 2π(81x  54x^3 + (81/5)x^5) from 0 to 1
= 2π(81  54 + 81/5  0)
= 432π/5 
khalid