# Verification on a x-axis rotation

• September 9th 2008, 04:36 PM
scycon
Verification on a x-axis rotation
The problem is as follows

"Consider the solid obtained by rotating the region bounded by the given curves about the x-axis.

y=5/x, x=8, x=16, y=0

Find the volume V of this solid."

For a solution I get

pi(5ln(16)-5ln(8))

Is this correct? I am asking because i've done the problem multiple times and am submitting it electronically for homework but it won't accept it or any other simplified form.

It looks like you did $\int_{8}^{16} \pi \frac{5}{x}dx$, but the formula that you should use is $V=\int_{a}^{b} \pi [f(x)]^2dx$.