Volume radius problem

  • Thread starter frozen7
  • Start date
  • #1
164
0
The volume surrounded by y = x^2 , y=0, x=-2, x=-1 , revolved about y axis,by using cylindrical method.

The region is actually within x=-1 to -2 and it can actually same with x=1 to 2.

radius = 2-x
height = x^2

Is my assumption correct?
 

Answers and Replies

  • #2
Fermat
Homework Helper
872
1
Your radius should simply be x. With limits of: x = 1 to 2

You assumption about being able to use the region in the 1st quadrant is correct, yes.
 
  • #3
164
0
How come the radius should be x?
 
  • #4
Fermat
Homework Helper
872
1
The radius should be x because the radius of the cylinder is the distance from the origin.
The volume of revolution is about the y-axis, which passes through the origin. And you are finding the volumes of all the thin cylinders starting with cylinders with a radius of x = 1 to x= 2.

See here for a further treatment of the cylindrical method.
 
Last edited:
  • #5
164
0
Something wrong with the link you have given.
 
  • #6
Fermat
Homework Helper
872
1
Sorry 'bout that. Forgot to add in the url.
The link is fixed now.
 

Related Threads on Volume radius problem

  • Last Post
Replies
11
Views
2K
Replies
1
Views
6K
Replies
1
Views
4K
Replies
2
Views
4K
Replies
9
Views
2K
Replies
8
Views
956
Replies
9
Views
1K
  • Last Post
Replies
4
Views
2K
Top