Find the volume of the solid

Question

Using disks or washers, find the volume of the solid obtained by rotating the region bounded by the curves y=x, y=0, x=2, and x=4 about the line x=1 

Answer 1

Volume v = 2π∫₂⁴(x - 1)xdx = 2π(x³/3 - x²/2)₂⁴ = 2π[(64/3 - 8) - (8/3 - 2)] = 76π/3