Series Problem Help: Evaluating \int \frac{\sin x}{x} with Convergence Analysis

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In summary, the conversation discusses evaluating the integral of \frac{\sin x}{x} and the use of the power series representation of \sin x to determine if the series is absolutely convergent. The conversation concludes that it is absolutely convergent by using the ratio test.
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courtrigrad
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I want to evaluate [tex] \int \frac{\sin x}{x} [/tex].

So [tex] \sin x = \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n+1}}{(2n+1)!} [/tex]. Therefore [tex] \frac{\sin x}{x} = \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n}}{(2n+1)!} [/tex]. So would that mean:

[tex] \int \frac{\sin x}{x} = C + \sum_{n=0}^{\infty} (-1)^{n} \frac{x^{2n+1}}{2n+1(2n+1)!} [/tex] would be absolutely convergent (i.e. [tex] R = \infty [/tex])?

Thanks
 
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  • #2
How do you know that series is absolutely convergent?
 
  • #3
I would use the ratio test [tex] |\frac{ a_{n+1}}{a_{n}}| [/tex]. If the limit as [tex] n\rightarrow \infty [/tex] is less than 1, then the series is absolutely convergent. Ok so I guess it is then.
 

FAQ: Series Problem Help: Evaluating \int \frac{\sin x}{x} with Convergence Analysis

What is the purpose of evaluating \int \frac{\sin x}{x}?

The purpose of evaluating \int \frac{\sin x}{x} is to find the value of the definite integral, which represents the area under the curve of \frac{\sin x}{x} between two given points on the x-axis.

What is the convergence analysis of \int \frac{\sin x}{x}?

The convergence analysis of \int \frac{\sin x}{x} involves determining whether the integral converges or diverges. This is important to know in order to properly evaluate the integral and obtain an accurate result.

How is convergence determined for \int \frac{\sin x}{x}?

The convergence of \int \frac{\sin x}{x} can be determined by using various tests, such as the comparison test, limit comparison test, or the integral test. These tests involve comparing the given integral to a known convergent or divergent series.

What is the significance of convergence for \int \frac{\sin x}{x}?

The convergence of \int \frac{\sin x}{x} is significant because it determines whether the integral has a finite value or not. If the integral converges, it means that the area under the curve is finite and can be accurately calculated. If it diverges, the integral does not have a finite value and cannot be properly evaluated.

Can \int \frac{\sin x}{x} be evaluated using any other methods?

Yes, \int \frac{\sin x}{x} can also be evaluated using techniques such as integration by parts or substitution. However, these methods may not always be applicable or may be more complex compared to using convergence analysis to evaluate the integral.

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