Question

find volume of the solid generated by revolving the area between the curve y=cosx/x and the x-axis for pi/6≤x≤pi/2 about the y-axis.

Answer 1

this must be solved by "Sheel method" to find the volumes

Answer 2

can you give me the source to learn?

Answer 3

\[
V=2\pi\int_a^b r(x)y(x)dx
\]
where
r(x) = radius of the shell.. how far is the shell from the axis of rotation
y(x) = height of the shell
dx = thickness of the shell

Answer 4

now, here
we find the shell at a distance of "x" from the axis of rotation
the height of the shell at that location is: \(y={\cos x\over x}\)
the limits are from \({\pi\over6}\le x\le{\pi\over2}\)

Answer 5

I have no clue to solve this. Please give me a way to learn.

Answer 6

see
http://www.khanacademy.org/math/calculus/solid_revolution_topic/shell-method/v/shell-method-for-rotating-around-vertical-line
for a short video on this method