Optimizing Limits of Integration for Change of Variables

In summary, the conversation was about a change of variables problem in which the domain of integration was a rectangle in the 1st quadrant with specific vertices. The person was unsure of how to choose the limits of integration for the new variables and expressed their doubts and progress in the conversation. Eventually, they provided the general limits of integration for three separate double integrals that would solve the problem.
  • #1
eyesontheball1
31
0
Hi guys, I've been on quite a random change of variables binge lately and I've been messing around with a particular scenario in which I'm not 100% sure of how I should choose my limits of integration. Any help would be greatly appreciated! (And no, this is not homework, etc.) The scenario is as follows:

Domain of integration in the xy plane is some rectangle in the 1st quadrant with vertices (a,c), (b,c), (a,d), (b,d), and I want to make a change of variables using x = u + [itex]\sqrt{u^2 - v^2}[/itex] and y = u - [itex]\sqrt{u^2 - v^2}[/itex]. Other than the fact that this transformation would inherently require v≤u, I'm just not certain on how to determine the other numerical limits of integration for u and v.
 
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  • #2
Update: I think I may have the bounds correct now. If not, someone please correct me. To make this change of variables, you have to express the new integration problem as three separate double integrals, with each of the double integrals having the following general limits of integration:

DI#1: [itex]\frac{a+c}{2}[/itex]≤u≤[itex]\sqrt{bd}[/itex] ; [itex]\frac{a+c}{2}[/itex]≤v≤u

DI#2: [itex]\frac{a+c}{2}[/itex]≤u≤[itex]\frac{b+d}{2}[/itex] ; [itex]\sqrt{ac}[/itex]≤v≤[itex]\frac{a+c}{2}[/itex]

DI#3: [itex]\sqrt{bd}[/itex]≤u≤[itex]\frac{b+d}{2}[/itex] ; [itex]\frac{a+c}{2}[/itex]≤v≤[itex]\sqrt{bd}[/itex]
 

Related to Optimizing Limits of Integration for Change of Variables

What is a "Limits of integration problem"?

A "Limits of integration problem" is a type of mathematical problem that involves finding the upper and lower boundaries of an integral. These boundaries, also known as limits, determine the range over which the integral is evaluated.

Why do we need to find the limits of integration?

The limits of integration are necessary in order to accurately calculate the value of an integral. Without these boundaries, the integral would not have a defined range and therefore would not have a precise value.

How do we determine the limits of integration?

The limits of integration can be determined by examining the problem and identifying the range over which the integral is being evaluated. This can also be done by graphing the function and visually identifying the boundaries.

What happens if the limits of integration are incorrect?

If the limits of integration are incorrect, the calculated value of the integral will also be incorrect. This can result in an inaccurate solution to the problem and potentially lead to incorrect conclusions.

Are there any shortcuts or tricks for finding the limits of integration?

While there are some techniques and strategies that can make finding the limits of integration easier, there is no universal shortcut for all types of integration problems. It is important to carefully analyze the problem and use mathematical reasoning to determine the appropriate limits.

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