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Volume of revolution

  • Thread starter ductape
  • Start date
18
0
The question I need to solve for an assignment is as follows:
Find the volume of the solid that is obtained by revolving the region R around the x-axis.

I figured that the volume would just be the integral of pi R^2 dx, so that would just be pi R^2 x, but that is not the answer. I suspect I am misinterpreting the question.
 

Answers and Replies

cristo
Staff Emeritus
Science Advisor
8,056
72
Well, R is probably a function of x. If you write the question, as stated, then we'll be more able to help you!
 
18
0
My problem is that that is the problem as stated. It doesn't give a function in terms of x.
 
18
0
Ah nevermind, I found out that the question was referring to an area already found in a previous question.
 
Gib Z
Homework Helper
3,344
4
Yes, and if it didn't specify the function, it would be [tex]\pi\int^b_a R^2 dx[/tex] anyway, where R is the closed interval (a,b).
 
HallsofIvy
Science Advisor
Homework Helper
41,734
893
Even that wouldn't make sense! If R is an interval it is not a number! I think both you and ductape are confusing the interval R with "radius" R.
 

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