Non-elementary Integral: Solving x^2sin(x)/(1+x^6) using Substitution Method

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In summary, the conversation discusses solving the integral of a given function using the substitution method and the possibility of using other methods. It is mentioned that the function is odd on the given interval and that the result involves sine and cosine integrals and imaginary parts. The conversation also includes a question about the level of difficulty for this problem.
  • #1
phil ess
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Homework Statement



Solve the integral of x2sin(x) / (1+x6) from -pi/2 to pi/2.

Homework Equations



none

The Attempt at a Solution



Well I am supposed to do this using the substitution method, so I tried:

u = x2
du = 2x dx which doesn't cancel out any terms

u = 1+x6
du = 6x5 dx which again doesn't cancel anything out

u = sin(x)
du = cox(x) dx useless also

Is this possible with substitution? I seem to have tried every option for u. Is there another way to do this? (without taylor series and stuff like that)

Thanks for the help!Also, I tried doing this integral on the computer, and it said it cannot be solved because it is probably a "non-elementary integral", hence the title of the thread.
 
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  • #2
The function is odd on that interval. f(-x)=-f(x).
 
Last edited:
  • #3
I had a similar question earlier. The result is a whole bunch of sine and cosine integrals and imaginary parts. I don't understand how one would do this, but go ahead and put it in the integrator (mathematica) and check the answer out. What level is this for?
 
  • #4
For a symmetric function that is odd, the integral on the interval -a to a = 0 !
Thanks guys.
 

1. What is a non-elementary integral?

A non-elementary integral is an integral that cannot be expressed in terms of elementary functions such as polynomials, exponential functions, and trigonometric functions. It may involve special functions or cannot be solved using traditional integration techniques.

2. How is a non-elementary integral different from an elementary integral?

An elementary integral can be solved using standard integration techniques, while a non-elementary integral requires more advanced methods or cannot be solved at all. Non-elementary integrals are often more complex and may involve special functions or infinite series.

3. What are some examples of non-elementary integrals?

Some examples of non-elementary integrals include the Fresnel integral, the elliptic integral, and the Bessel function integral. These integrals cannot be expressed in terms of elementary functions and require special techniques or numerical methods to solve.

4. How are non-elementary integrals used in science?

Non-elementary integrals are used in a variety of scientific fields, including physics, engineering, and mathematics. They are commonly used in solving differential equations and in modeling physical systems. They also have applications in statistics, finance, and other areas of research.

5. What techniques are used to solve non-elementary integrals?

Special techniques such as contour integration, series expansions, and numerical methods are often used to solve non-elementary integrals. In some cases, computer software or algorithms may be used to approximate the integral. Additionally, many non-elementary integrals have known closed-form solutions involving special functions.

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