Quote:
Originally posted by Xantar
Is this another case of your teacher insisting that you use a more complicated method than necessary? 
If the graph were bounded on the y-axis from, say, 0 to 3, I'd agree with you. But the graph is bounded from 0 to 4. Plug in any value you want for x and you'll see that the y-value never goes above 4. The boundaries set by the problem are meaningless because the graph never goes beyond those boundaries anyway.
Oh, and by the way, your integration is wrong. It's the correct integration for 16 - (x squared), but you forgot that the entire equation is under a square root.
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Actually the integration is correct.. you don't know the full formula for the area of a region bounded by either axis
It's
Pi times the integration of {R(X)}²dx
So I skipped the step where I took out the square..
As a square root squared would give you what ever was inside the sign.. I assumed you knew that much
And actually that is the way to do iyt.. there is also a pic in the book