easy way: use Theorem of Pappus to get volume
v = Ad
where A is area of ellipse and d is the distance traveled by the centroid.
Area of ellipse = πab = 3π
radius of revolution is 5, so d = 10π
Volume of solid of revolution is 30π^2
find the volume generated when the ellipse x^2/9 + y^2 = 1 is rotated around the line y=5
1 answer