Set up the integral that uses the method of disks/washers to find the volume V of the solid obtained by rotating the region bounded by the given curves about the specified lines.

Question

Y=x^2/4 +3 , Y=3, x=8

a) about the line y=20

b) about the line y=1

Answer 1

In either case, use

V = π∫_a^b|[(d-f(x))²-(d-g(x))²]|dx

Where d is the line rotate about

'a' is the x-value where f(x)=g(x)

'b' is the right most x-value, in this case, 8