Iterated Integrals bounded by curves

  • #1
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Main Question or Discussion Point

Evaluate [tex]\int[/tex][tex]\int_{Q}\left(1 - x^{3}\right)y^{2} dA[/tex] where Q is the region bounded by y=x^2 and x = y^2

So I have drew the graphs of y=x^2 and x=y^2 and found that they intersect at (0,0) and (1,1). Now I am confused what to replace Q with, but I think it should be this: please tell me if I am incorrect in my selection.

[tex]\int^{1}_{0}[/tex][tex]\int_{\sqrt{y}}^{y^{2}}\left(1 - x^{3}\right)y^{2} dx dy[/tex]

or should I be integrating w.r.t y first? also have I mixed up the y^2 and the sqrt(y) in the limit of integration?
 

Answers and Replies

  • #2
EnumaElish
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dxdy is correct, but sqrt(y) > y^2.
 
  • #3
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how would i know this for future reference, i am having serious trouble with the limit of integration part.
 
  • #4
Hurkyl
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Well, it's clear that either [itex]\sqrt{y} < y^2[/itex] for every y in that interval, or [itex]y^2 < \sqrt{y}[/itex] for every y in that interval, correct?

So, if you try one actual value of y in that interval...


A little algebra would solved it too: what happens if you manipulate that inequality to put all of the y's on the same side?
 

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