VOL CROSS-SECTION DISK WASHER

Question

Using disks or washers, find the volume of the solid obtained by rotating the region bounded by the curves 𝑦=sqrt(x-1),y=0, x=2,x=4 about the x-axis.

Answer 1

V=π ∫₂⁴(x-1)dx= π [x²/2- x]₂⁴=4π