Solve Improper Integral: $\int_{1}^{\infty} 1/(x^2+ 3 \ |sin x| +2) dx$

In summary: So basically I have to show that it converges or diverges.In summary, the conversation is discussing a homework problem involving finding the improper integral of a given function. The person is unsure of how to solve the integral and is seeking assistance. The expert suggests using a comparison test to prove the existence of the improper integral.
  • #1
Archimedes II
7
0

Homework Statement



[itex]\displaystyle \int_{1}^{\infty} 1/(x^2+ 3 \ |sin x| +2) dx [/itex]

Homework Equations



N/A

The Attempt at a Solution



[itex]\displaystyle \int_{1}^{\infty} 1/(x^2+ 3 \ |sin x| +2) dx =[/itex]

[itex]\displaystyle lim_{t\rightarrow \infty} \int_{1}^{t} 1/(x^2+ 3 \ |sin x| +2) dx [/itex]

Side Work

[itex]\displaystyle \int 1/(x^2+ 3 \ |sin x| +2) dx [/itex]

I have now clue how to solve this integral. It can't be simplified. U substitution doesn't work nor does a trigonometric substitution. Once I can solve the indefinite itegral I can solve the rest on my own.

Thanks in advance.
 
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  • #2
Archimedes II said:

Homework Statement



[itex]\displaystyle \int_{1}^{\infty} 1/(x^2+ 3 \ |sin x| +2) dx [/itex]


Homework Equations



N/A


The Attempt at a Solution



[itex]\displaystyle \int_{1}^{\infty} 1/(x^2+ 3 \ |sin x| +2) dx =[/itex]

[itex]\displaystyle lim_{t\rightarrow \infty} \int_{1}^{t} 1/(x^2+ 3 \ |sin x| +2) dx [/itex]

Side Work

[itex]\displaystyle \int 1/(x^2+ 3 \ |sin x| +2) dx [/itex]

I have now clue how to solve this integral. It can't be simplified. U substitution doesn't work nor does a trigonometric substitution. Once I can solve the indefinite itegral I can solve the rest on my own.

Thanks in advance.

You can't solve the indefinite integral. You just want to prove the improper integral exists. Try a comparison test.
 
  • #3
Dick said:
You can't solve the indefinite integral. You just want to prove the improper integral exists. Try a comparison test.

Oh ok thanks that makes since now.
 

1. What is an improper integral?

An improper integral is an integral where one or both of the limits of integration are infinite, or the integrand function becomes undefined at a certain point within the limits of integration.

2. How do you solve an improper integral?

To solve an improper integral, you need to first identify the type of improper integral it is (infinite limit, discontinuous integrand, etc.). Then, you can use techniques such as limit comparison, partial fractions, or substitution to transform the integral into a form that can be evaluated using standard integration methods.

3. Why is this integral improper?

This integral is improper because the upper limit of integration is infinite, making the integral unbounded.

4. What is the strategy for solving this particular improper integral?

The strategy for solving this specific improper integral is to use the substitution method by letting u = sin x. This will transform the integral into a form that can be evaluated using standard integration techniques.

5. Can this improper integral be solved using any other method?

Yes, this improper integral can also be solved using the limit comparison method by comparing it to a known convergent or divergent integral. However, the substitution method is typically simpler and more efficient for this integral.

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