Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified line. Sketch the region, the solid, and a typical disk or washer.(adsbygoogle = window.adsbygoogle || []).push({});

y = x

y = [tex]\sqrt{x}[\tex]

rotate about y = 1

http://img461.imageshack.us/img461/5879/math10sp.jpg [Broken]

=http://img161.imageshack.us/img161/5729/math23gk.th.jpg [Broken]

So, I am integrating with respect to x.

Area = [tex]\int^1_{0}\pi[(f(x))^2-(g(x))^2]dx[\tex]

I assumed that f(x) = x and g(x) = [tex]\sqrt{x}[\tex].

However, the book gives f(x) = 1 - x and g(x) = 1 - [tex]\sqrt{x}[\tex].

I don't understand how they got that.

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# Integral and volume

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