Find the volume V of the solid obtained by rotating the region bounded by the given curves about the specified line.
y = 3sqrt64 − x^2, y = 0, x = 4, x = 5 about the x-axis
using discs,
v = ∫[4,5] πr^2 dx
where r = y = 3√(64-x^2)
v = ∫[4,5] π*9(64-x^2) dx