Find the volume

Question

Using disks or washers, find the volume of the solid obtained by rotating the region bounded by the curves y=√(x-1), y=0, x=2, and x=5 about the x-axis.

 

What is the volume?

Answer 1

By disk method volume v = π ∫₂⁵(x - 1)dx = π(x - 1)²/2₂⁵ = π(8 - 1/2) = 15π/2