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# Help with volume of revolution Watch

1. I cannot seem to get the answer to part C. I have tried finding the volume of revolution of each shape then taking away the vol of rev of y=2/x from y=3-x.
I have also tried

pi Integral [(3-x)2 - (2/x)2]

The answer to C is pi/3 u3

The answer to A is (1,2) (2,1)
The answer to B is 3/2 - 2ln2

2. what you have used is fine:

(EDITED FIRST PART)
3. (Original post by Hasufel)
what you have used is fine:

(EDITED FIRST PART)
thank you! I now know where i was going wrong, when I turned (3-x)2 into 9-x2 then tried to integrate. Do you know why this would not work?
4. (Original post by Hasufel)
what you have used is fine:

(EDITED FIRST PART)
Oh wait nevermind! I know now haha, im messing up basics (3-x)2 = (3-x)(3-x)
5. (Original post by Tomupcraft)
thank you! I now know where i was going wrong, when I turned (3-x)2 into 9-x2 then tried to integrate. Do you know why this would not work?
the expansion of is:

which is

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