9x=y^2+18 between 2&6..so y=(9x-18)^1/2(adsbygoogle = window.adsbygoogle || []).push({});

and dy/dx= [tex] \frac{9}{2 \sqrt{9x-18}}[/tex]

so [tex]S = 2 \pi \int_2^6 \sqrt{9x-18} \sqrt{1+ \frac{81}{36x+72}}dx[/tex]

If this is all right..then I am stuck :grumpy:

Any help?

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# Homework Help: Area of a surface of revolution

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