How to do this kind of integral?

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In summary, the limits of integration for a given integral can be determined by examining the boundaries of the region being integrated over and potentially sketching a diagram. To solve a difficult integral, it is best to try different methods such as substitution, integration by parts, or trigonometric identities. To check if an integral has been solved correctly, one can differentiate the answer or use a graphing calculator to compare it to the original function. If an integral cannot be solved analytically, it can still be solved numerically using methods like Simpson's rule or the trapezoidal rule. Integration is a powerful tool for solving real-world problems in various fields, such as finding areas, volumes, and analyzing continuous systems.
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Homework Statement


I want to evaluate, using residue calculus, the following
[tex]\int_0^{\infty}\frac{xdx}{1+x^4}[/tex]
I can't find any kind of formula for this kind of integral though. We just know [tex]\int_{-\infty}^{\infty}\frac{P(x)dx}{Q(x)}[/tex], however that would give 0 in this case as the function is odd. Any pointers?

Homework Equations


The Attempt at a Solution

 
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Err... figured it out. Just have to use a the contour with a quarter-arc, then along the y-axis, then the x-axis...
 

1. How do I determine the limits of integration for a given integral?

The limits of integration are determined by the bounds of the region being integrated over. This can be determined by examining the problem and identifying the boundaries of the region. It may also be helpful to sketch a graph or diagram to visualize the region.

2. What is the best method for solving a difficult integral?

The best method for solving a difficult integral depends on the specific integral and the techniques available. Some common methods include substitution, integration by parts, and trigonometric identities. It is important to try different methods and see which one yields the most straightforward solution.

3. How do I know if I have solved an integral correctly?

You can check your answer by differentiating it and seeing if you get back to the original function. This is known as the Fundamental Theorem of Calculus. Alternatively, you can use a graphing calculator to plot the original function and the integral and see if they match.

4. Can integrals be solved numerically if they cannot be solved analytically?

Yes, integrals can be solved numerically using methods such as Simpson's rule or the trapezoidal rule. These methods approximate the integral by dividing the region into smaller subintervals and using the area of trapezoids or parabolas to estimate the integral.

5. How can I use integration to solve real-world problems?

Integration is a powerful tool for solving real-world problems in fields such as physics, engineering, and economics. It can be used to find areas, volumes, and other quantities that are difficult to measure directly. It is also used to model and analyze continuous systems, such as population growth or fluid flow.

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