Answer:
A) The volume of solid is 18π cubic unit.
B) The volume of sphere is
a = -r , b = r , and
Solution A)
The given curve, rotate about x-axis between 2 to 4.
Please find attachment for solid figure or rotation.
Using disk method to find the volume rotation about x-axis
where, a = 2, b= 4 , and dx is thickness of disk.
Hence, the volume of solid is 18π cubic unit
Solution B)
The equation of circle of radius r and centered at origin (0,0).
The solid form is sphere of radius r.
Using disk method, to find volume of solid
where, a = -r, b = r , and dx is thickness of disk.
Hence, the volume of sphere is
