Tom K. answered 08/08/20
Knowledgeable and Friendly Math and Statistics Tutor
x = y^8, x = 0, and y = 1 defines the region rotated about x = 5.
Then, we subtract the volume created by the x = y^8 from the volume created by x = 0.
x = y^8 meets x = 0 at y = 0.
The volume from x = 0 is a cylinder, πr2h = π52(1-0) = 25π
The distance of x = y^8 from x = 5 is 5 - y^8
Then, using I[a,b] for the integral from a to b and E[a,b] for the evaluation from a to b, we use the disk method, and
I[0, 1] π(5 - y^8)2 dy = π I[0, 1] 25 - 10y^8 + y^16 dy = π(25y - 10/9 y^9 + y^17/17) E[0,1] =
π(25 - 10/9 + 1/17 -(0)) = π(25 - 10/9 + 1/17)
Then, 25π - π(25 - 10/9 + 1/17) = 10/9π - 1/17π = 1 8/153 π or 161/153 π