Finding Two-Term Asymptotic Expansion for Real Roots of xe-x=epsilon

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In summary, an asymptotic expansion is a mathematical technique used to approximate a function or series with a simpler, more manageable expression. It differs from a Taylor series in that it is only an approximation and has limitations in its validity and accuracy. The purpose of using an asymptotic expansion is to simplify complex functions and gain insight into their behavior. It is commonly used in fields such as physics, engineering, and statistics, with examples including the error function, Bessel functions, and the Gaussian distribution. However, it is important to consider the limitations and applicability of the expansion when using it in problem-solving.
  • #1
haywood
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Can anyone tell me how to find a two-term asymptotic expansion for the two real roots of xe-x=epsilon as epsilon --> 0

Thanks,
A.Haywood
 
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  • #2
dear Haywood
I don't know what kind of asypmtotic expasion you are looking for, so a short hint on how to solve the equation approximatly must suffice.
For the root near 0 substitute the left hand side with a taylor polynomial.
For the other root take logarithms on both sides.
 
  • #3
That works! I was especially looking for how to find that second root, so grateful that you mentioned using ln :-)
Thank you, Dalle!
 

FAQ: Finding Two-Term Asymptotic Expansion for Real Roots of xe-x=epsilon

What is an asymptotic expansion?

An asymptotic expansion is a mathematical technique used to approximate a function or series with a simpler, more manageable expression. It is often used in situations where the exact solution is difficult or impossible to obtain.

How does an asymptotic expansion differ from a Taylor series?

An asymptotic expansion is a type of approximation, while a Taylor series is an exact representation of a function. An asymptotic expansion only holds true for a certain range of values, while a Taylor series is valid for all values within the function's domain.

What is the purpose of using an asymptotic expansion?

The purpose of using an asymptotic expansion is to simplify complex functions or series, making them easier to work with and analyze. It can also provide insight into the behavior of a function as its input approaches certain values.

What are some common examples of functions that use asymptotic expansions?

Asymptotic expansions are commonly used in fields such as physics, engineering, and statistics. Examples include the error function, Bessel functions, and the Gaussian distribution.

Are there any limitations to using an asymptotic expansion?

Yes, there are some limitations to using an asymptotic expansion. It is only valid for certain ranges of values, and as the number of terms in the expansion increases, the accuracy decreases. It is also important to consider the applicability of the expansion to the specific problem at hand.

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