Surface of Revolution: under xy=9 and to the right of x=1

Snowdog2112

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Apr 30, 2006
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Show that when the portion R of the plane under x*y=9 and to the right of x=1 is revolved about the x-axis the volume generated is 81pi cu. in. but the area of the surface is infinite.

I have absolutely no idea how to get this one going, and I couldn't find anything like it in the book.
 
Washers:

\(\displaystyle \L\\{\pi}\int_{1}^{\infty}(\frac{9}{x})^{2}dx\)


Surface of revolution:

\(\displaystyle \L\\2{\pi}\int_{1}^{\infty}(\frac{9}{x}\sqrt{1+\frac{81}{x^{4}}})dx\)
 
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