Iterated Integrals bounded by curves

In summary, the conversation is discussing how to evaluate the double integral of (1-x^3)y^2 over the region bounded by y=x^2 and x=y^2. The correct integral is found to be \int^{1}_{0}\int_{\sqrt{y}}^{y^{2}}\left(1 - x^{3}\right)y^{2} dx dy, with the limits of integration determined by the intersection points of the two graphs. The discussion also touches on the importance of paying attention to the limits of integration and using algebra to simplify the process.
  • #1
braindead101
162
0
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?
 
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  • #2
dxdy is correct, but sqrt(y) > y^2.
 
  • #3
how would i know this for future reference, i am having serious trouble with the limit of integration part.
 
  • #4
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?
 

FAQ: Iterated Integrals bounded by curves

What is an iterated integral bounded by curves?

An iterated integral bounded by curves is a type of integration where the limits of integration are given by curves instead of constants. This means that the integration is done over a region that is bounded by two or more curves.

How is an iterated integral bounded by curves different from a regular integral?

In a regular integral, the limits of integration are constants, while in an iterated integral bounded by curves, the limits are curves. This means that the region of integration is not a rectangle or a box, as it would be in a regular integral, but instead can have a more complex shape determined by the bounding curves.

What is the purpose of using iterated integrals bounded by curves?

Iterated integrals bounded by curves are used to find the volume, area, or other quantities of irregularly shaped regions. They are also used in various applications in physics, engineering, and economics to solve problems involving curved boundaries.

How do you evaluate an iterated integral bounded by curves?

To evaluate an iterated integral bounded by curves, you must first determine the order of integration, which is the order in which the integrals are evaluated. Then, you must set up the integral using the appropriate limits of integration based on the given curves. Finally, you can evaluate the integral using standard integration techniques.

What are some common challenges when working with iterated integrals bounded by curves?

Some common challenges when working with iterated integrals bounded by curves include determining the correct order of integration, setting up the integral with the correct limits of integration, and dealing with complex or overlapping bounding curves. Additionally, evaluating the integral can be challenging if the integrand is complex or if the region of integration is irregularly shaped.

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