Confused about cylindrical shell radius?
For the region bounded by y=x^4, y=0 and x=1; rotated about x=2, the radius of a typical shell is 2-x.
But, for the region bounded by y=4x-x^2 and y=3; rotated about x=1, the radius of a typical shell is x-1.
Can anyone explain why the radius is x-1, instead of 1-x? Or what's the thought process behind figuring out what the radius of a shell is?
For the region bounded by y=x^4, y=0 and x=1; rotated about x=2, the radius of a typical shell is 2-x.
But, for the region bounded by y=4x-x^2 and y=3; rotated about x=1, the radius of a typical shell is x-1.
Can anyone explain why the radius is x-1, instead of 1-x? Or what's the thought process behind figuring out what the radius of a shell is?
1 Answer
Mar 9, 2018
In the second case,
Explanation:
Sketch the graphs.
In the first problem
In the second problem the axis of rotation is to the left of