Can someone explain problem #9 on the practice final for me? I'm totally confused as to how their geometric description of the region "R" ends up being the circle given...

Also, on problem #18, why does the range for theta only go from 0 to (pi)/2? How are they getting those bounds?

Question

Can someone explain problem #9 on the practice final for me?  I'm totally confused as to how their geometric description of the region "R" ends up being the circle given...

Also, on problem #18, why does the range for theta only go from 0 to (pi)/2?  How are they getting those bounds?

phi · Answer

Are you asking about this one: http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/final-exam-1/practice-final-exam/MIT18_02SC_pracfinal.pdf ? If so, do you mean problem 10? (problem 9 does not have any circle)

anonymous · Answer

Oh shoot, yeah, I did mean #10!

Can you help Phi?  You've explained a bunch of things that've confused me in the past, really, really well, and I just wanted to let you know how much I appreciate it :).

phi · Answer

I can't make any sense of Problem 10.

For problem 18, 
in rectangular coords x and y, the limits are 0 to infinity
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