Washer Method Problem that is revolved about the x-axis? R and r?

Posted on 2016-02-16 17:14:00 in Math by KELLY

The region bounded by y=2/(x+1), y=x, and the y-axis is revolved about the x-axis. Find the volume of the resulting solid using the disk method or the washer method as appropriate... 

I would like to know if R is supposed to be 2/(x+1) -x and r is just x. If so, I get an answer of 2pi(ln(4)-1) 

However, if I do it the other way making R just 2/(x+1), I get an answer of 2pi/3.. I think the first way is correct but I am not entirely sure.. 

Any help is greatly appreciated!

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